Proteins, usually glycoproteins, found in the viral envelopes of a variety of viruses. They promote cell membrane fusion and thereby may function in the uptake of the virus by cells.
The adherence and merging of cell membranes, intracellular membranes, or artificial membranes to each other or to viruses, parasites, or interstitial particles through a variety of chemical and physical processes.
The entering of cells by viruses following VIRUS ATTACHMENT. This is achieved by ENDOCYTOSIS, by direct MEMBRANE FUSION of the viral membrane with the CELL MEMBRANE, or by translocation of the whole virus across the cell membrane.
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
Fusion of somatic cells in vitro or in vivo, which results in somatic cell hybridization.
Layers of protein which surround the capsid in animal viruses with tubular nucleocapsids. The envelope consists of an inner layer of lipids and virus specified proteins also called membrane or matrix proteins. The outer layer consists of one or more types of morphological subunits called peplomers which project from the viral envelope; this layer always consists of glycoproteins.
A subgroup of the genus FLAVIVIRUS that causes encephalitis and hemorrhagic fevers and is found in eastern and western Europe and the former Soviet Union. It is transmitted by TICKS and there is an associated milk-borne transmission from viremic cattle, goats, and sheep.
A class I viral fusion protein that forms the characteristic spikes, or peplomers, found on the viral surface that mediate virus attachment, fusion, and entry into the host cell. During virus maturation, it is cleaved into two subunits: S1, which binds to receptors in the host cell, and S2, which mediates membrane fusion.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Multinucleated masses produced by the fusion of many cells; often associated with viral infections. In AIDS, they are induced when the envelope glycoprotein of the HIV virus binds to the CD4 antigen of uninfected neighboring T4 cells. The resulting syncytium leads to cell death and thus may account for the cytopathic effect of the virus.
Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A CELL LINE derived from the kidney of the African green (vervet) monkey, (CERCOPITHECUS AETHIOPS) used primarily in virus replication studies and plaque assays.
A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Established cell cultures that have the potential to propagate indefinitely.
A species of CORONAVIRUS causing atypical respiratory disease (SEVERE ACUTE RESPIRATORY SYNDROME) in humans. The organism is believed to have first emerged in Guangdong Province, China, in 2002. The natural host is the Chinese horseshoe bat, RHINOLOPHUS sinicus.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
Glycoproteins found on the membrane or surface of cells.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Transmembrane envelope protein of the HUMAN IMMUNODEFICIENCY VIRUS which is encoded by the HIV env gene. It has a molecular weight of 41,000 and is glycosylated. The N-terminal part of gp41 is thought to be involved in CELL FUSION with the CD4 ANTIGENS of T4 LYMPHOCYTES, leading to syncytial formation. Gp41 is one of the most common HIV antigens detected by IMMUNOBLOTTING.
A subfamily of PARAMYXOVIRIDAE. Genera include RUBULAVIRUS; RESPIROVIRUS; MORBILLIVIRUS; HENIPAVIRUS; and AVULAVIRUS.
The GENETIC TRANSLATION products of the fusion between an ONCOGENE and another gene. The latter may be of viral or cellular origin.
The GENETIC RECOMBINATION of the parts of two or more GENES resulting in a gene with different or additional regulatory regions, or a new chimeric gene product. ONCOGENE FUSION includes an ONCOGENE as at least one of the fusion partners and such gene fusions are often detected in neoplastic cells and are transcribed into ONCOGENE FUSION PROTEINS. ARTIFICIAL GENE FUSION is carried out in vitro by RECOMBINANT DNA technology.
Operative immobilization or ankylosis of two or more vertebrae by fusion of the vertebral bodies with a short bone graft or often with diskectomy or laminectomy. (From Blauvelt & Nelson, A Manual of Orthopaedic Terminology, 5th ed, p236; Dorland, 28th ed)
Specific hemagglutinin subtypes encoded by VIRUSES.
Glycoprotein from Sendai, para-influenza, Newcastle Disease, and other viruses that participates in binding the virus to cell-surface receptors. The HN protein possesses both hemagglutinin and neuraminidase activity.
Membrane glycoproteins from influenza viruses which are involved in hemagglutination, virus attachment, and envelope fusion. Fourteen distinct subtypes of HA glycoproteins and nine of NA glycoproteins have been identified from INFLUENZA A VIRUS; no subtypes have been identified for Influenza B or Influenza C viruses.
A genus of the family PARAMYXOVIRIDAE (subfamily PARAMYXOVIRINAE) where all the virions have both HEMAGGLUTININ and NEURAMINIDASE activities and encode a non-structural C protein. SENDAI VIRUS is the type species.
Inhibitors of the fusion of HIV to host cells, preventing viral entry. This includes compounds that block attachment of HIV ENVELOPE PROTEIN GP120 to CD4 RECEPTORS.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Specific molecular components of the cell capable of recognizing and interacting with a virus, and which, after binding it, are capable of generating some signal that initiates the chain of events leading to the biological response.
Proteins that catalyze MEMBRANE FUSION.
A species of RESPIROVIRUS also called hemadsorption virus 2 (HA2), which causes laryngotracheitis in humans, especially children.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
A sequential pattern of amino acids occurring more than once in the same protein sequence.
The infective system of a virus, composed of the viral genome, a protein core, and a protein coat called a capsid, which may be naked or enclosed in a lipoprotein envelope called the peplos.
Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.
A family of RNA viruses causing INFLUENZA and other diseases. There are five recognized genera: INFLUENZAVIRUS A; INFLUENZAVIRUS B; INFLUENZAVIRUS C; ISAVIRUS; and THOGOTOVIRUS.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
A species of ALPHAVIRUS isolated in central, eastern, and southern Africa.
Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells.
The type species of LENTIVIRUS and the etiologic agent of AIDS. It is characterized by its cytopathic effect and affinity for the T4-lymphocyte.
Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.
Proteins found in any species of virus.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
The type species of the genus INFLUENZAVIRUS A that causes influenza and other diseases in humans and animals. Antigenic variation occurs frequently between strains, allowing classification into subtypes and variants. Transmission is usually by aerosol (human and most non-aquatic hosts) or waterborne (ducks). Infected birds shed the virus in their saliva, nasal secretions, and feces.
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
The rate dynamics in chemical or physical systems.
Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.
Agents used in the prophylaxis or therapy of VIRUS DISEASES. Some of the ways they may act include preventing viral replication by inhibiting viral DNA polymerase; binding to specific cell-surface receptors and inhibiting viral penetration or uncoating; inhibiting viral protein synthesis; or blocking late stages of virus assembly.
Periplasmic proteins that bind MALTOSE and maltodextrin. They take part in the maltose transport system of BACTERIA.
A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
The GENETIC RECOMBINATION of the parts of two or more GENES, including an ONCOGENE as at least one of the fusion partners. Such gene fusions are often detected in neoplastic cells and are transcribed into ONCOGENE FUSION PROTEINS.
Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.
A transferase that catalyzes the addition of aliphatic, aromatic, or heterocyclic FREE RADICALS as well as EPOXIDES and arene oxides to GLUTATHIONE. Addition takes place at the SULFUR. It also catalyzes the reduction of polyol nitrate by glutathione to polyol and nitrite.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
Proteins prepared by recombinant DNA technology.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
A group of enzymes that catalyzes the hydrolysis of terminal, non-reducing beta-D-galactose residues in beta-galactosides. Deficiency of beta-Galactosidase A1 may cause GANGLIOSIDOSIS, GM1.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.
Proteins found in any species of bacterium.
DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
A type of chromosome aberration characterized by CHROMOSOME BREAKAGE and transfer of the broken-off portion to another location, often to a different chromosome.
Transport proteins that carry specific substances in the blood or across cell membranes.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
Crystallizable fragments composed of the carboxy-terminal halves of both IMMUNOGLOBULIN HEAVY CHAINS linked to each other by disulfide bonds. Fc fragments contain the carboxy-terminal parts of the heavy chain constant regions that are responsible for the effector functions of an immunoglobulin (COMPLEMENT fixation, binding to the cell membrane via FC RECEPTORS, and placental transport). This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme PAPAIN.

Definition of a major p53 binding site on Ad2E1B58K protein and a possible nuclear localization signal on the Ad12E1B54K protein. (1/1579)

Previous studies have established that adenovirus 2/5 early region 1B (Ad E1B) 58K protein binds p53 strongly and co-localizes with it to cytoplasmic dense bodies whilst the homologous Ad12E1B54K protein binds only weakly and co-localizes primarily to the nucleus in Ad12E1 transformed cells. We have used these properties of the E1B proteins from different viral serotypes to map the p53 binding site on the Ad2/5 protein. A set of chimaeric genes was constructed containing different proportions of the Ad12 and Ad2E1B DNA. These, together with Ad12E1A and E1B19K DNA, were transfected into baby rat kidney cells and transformed lines isolated. From an examination of the properties of these Ad12/Ad2E1B fusion proteins in co-immunoprecipitation and subcellular localization experiments it has been concluded that the p53 binding site on Ad2E1B58K protein lies between amino acids 216 and 235 and that the homologous region on Ad12E1B54K protein also binds p53. In addition, a unique nuclear localization signal is located on Ad12E1B54K between residues 228 and 239. We suggest that primary structure differences in these regions of the Ad2 and Ad12E1B proteins are responsible for the different subcellular localizations in AdE1 transformants.  (+info)

The cytoplasmic tail of the influenza C virus glycoprotein HEF negatively affects transport to the cell surface. (2/1579)

The surface glycoprotein, HEF, of influenza C virus (C/Johannesburg/1/66) has been shown to undergo a post-translation conformational change that is evident in a dramatic change of electrophoretic mobility. If the corresponding gene is expressed in the absence of other viral proteins, this folding process does not occur at all or only very inefficiently. A chimaeric protein, HEF-HA(Tail), in which the short cytoplasmic tail (Arg-Thr-Lys) of HEF was replaced by the cytoplasmic tail of the haemagglutinin of an influenza A virus (fowl plague virus) was constructed. In contrast to the wild-type protein, the chimaeric protein was detected on the cell surface. No further improvement of the surface expression was observed when both the transmembrane domain and the cytoplasmic tail were replaced by the corresponding domains of either the influenza A haemagglutinin or gp40, an endogenous protein of MDCK cells. For the HEF-HA(Tail) construct this study shows that a substantial amount of the protein is converted to the 100 kDa mature form that is observed in virus-infected cells. The HEF-HA expressed on the cell surface reacted positively in esterase and haemadsorption assays, indicating that it was present in a biologically active form. The results show that the short cytoplasmic tail of HEF has a negative effect on the folding and surface transport of this protein. How this effect may be prevented during a virus infection is discussed.  (+info)

Glycoprotein gL-independent infectivity of pseudorabies virus is mediated by a gD-gH fusion protein. (3/1579)

Envelope glycoproteins gH and gL, which form a complex, are conserved throughout the family Herpesviridae. The gH-gL complex is essential for the fusion between the virion envelope and the cellular cytoplasmic membrane during penetration and is also required for direct viral cell-to-cell spread from infected to adjacent noninfected cells. It has been proposed for several herpesviruses that gL is required for proper folding, intracellular transport, and virion localization of gH. In pseudorabies virus (PrV), glycoprotein gL is necessary for infectivity but is dispensable for virion localization of gH. A virus mutant lacking gL, PrV-DeltagLbeta, is defective in entry into target cells, and direct cell-to-cell spread is drastically reduced, resulting in only single or small foci of infected cells (B. G. Klupp, W. Fuchs, E. Weiland, and T. C. Mettenleiter, J. Virol. 71:7687-7695, 1997). We used this limited cell-to-cell spreading ability of PrV-DeltagLbeta for serial passaging of cells infected with transcomplemented virus by coseeding with noninfected cells. After repeated passaging, plaque formation was restored and infectivity in the supernatant was observed. One single-plaque isolate, designated PrV-DeltagLPass, was further characterized. To identify the mutation leading to this gL-independent infectious phenotype, Southern and Western blot analyses, radioimmunoprecipitations, and DNA sequencing were performed. The results showed that rearrangement of a genomic region comprising part of the gH gene into a duplicated copy of part of the unique short region resulted in a fusion fragment predicted to encode a protein consisting of the N-terminal 271 amino acids of gD fused to the C-terminal 590 residues of gH. Western blotting and radioimmunoprecipitation with gD- and gH-specific antibodies verified the presence of a gDH fusion protein. To prove that this fusion protein mediates infectivity of PrV-DeltagLPass, cotransfection of PrV-DeltagLbeta DNA with the cloned fusion fragment was performed, and a cell line, Nde-67, carrying the fusion gene was established. After cotransfection, infectious gL-negative PrV was recovered, and propagation of PrV-DeltagLbeta on Nde-67 cells produced infectious virions. Thus, a gDH fusion polypeptide can compensate for function of the essential gL in entry and cell-to-cell spread of PrV.  (+info)

Gene transfer to mammalian cells using genetically targeted filamentous bacteriophage. (4/1579)

We have genetically modified filamentous bacteriophage to deliver genes to mammalian cells. In previous studies we showed that noncovalently attached fibroblast growth factor (FGF2) can target bacteriophage to COS-1 cells, resulting in receptor-mediated transduction with a reporter gene. Thus, bacteriophage, which normally lack tropism for mammalian cells, can be adapted for mammalian cell gene transfer. To determine the potential of using phage-mediated gene transfer as a novel display phage screening strategy, we transfected COS-1 cells with phage that were engineered to display FGF2 on their surface coat as a fusion to the minor coat protein, pIII. Immunoblot and ELISA analysis confirmed the presence of FGF2 on the phage coat. Significant transduction was obtained in COS-1 cells with the targeted FGF2-phage compared with the nontargeted parent phage. Specificity was demonstrated by successful inhibition of transduction in the presence of excess free FGF2. Having demonstrated mammalian cell transduction by phage displaying a known gene targeting ligand, it is now feasible to apply phage-mediated transduction as a screen for discovering novel ligands.  (+info)

Identification of a coronavirus hemagglutinin-esterase with a substrate specificity different from those of influenza C virus and bovine coronavirus. (5/1579)

We have characterized the hemagglutinin-esterase (HE) of puffinosis virus (PV), a coronavirus closely related to mouse hepatitis virus (MHV). Analysis of the cloned gene revealed approximately 85% sequence identity to HE proteins of MHV and approximately 60% identity to the corresponding esterase of bovine coronavirus. The HE protein exhibited acetylesterase activity with synthetic substrates p-nitrophenyl acetate, alpha-naphthyl acetate, and 4-methylumbelliferyl acetate. In contrast to other viral esterases, no activity was detectable with natural substrates containing 9-O-acetylated sialic acids. Furthermore, PV esterase was unable to remove influenza C virus receptors from human erythrocytes, indicating a substrate specificity different from HEs of influenza C virus and bovine coronavirus. Solid-phase binding assays revealed that purified PV was unable to bind to sialic acid-containing glycoconjugates like bovine submaxillary mucin, mouse alpha1 macroglobulin or bovine brain extract. Because of the close relationship to MHV, possible implications on the substrate specificity of MHV esterases are suggested.  (+info)

Highly diverse intergenic regions of the paramyxovirus simian virus 5 cooperate with the gene end U tract in viral transcription termination and can influence reinitiation at a downstream gene. (6/1579)

A dicistronic minigenome containing the M-F gene junction was used to determine the role of the simian virus 5 (SV5) intergenic regions in transcription. The M-F junction differs from the other SV5 junctions by having a short M gene end U tract of only four residues (U4 tract) and a 22-base M-F intergenic sequence between the M gene end and F gene start site. Replacing the 22-base M-F intergenic region with nonviral sequences resulted in a minigenome template (Rep 22) that was defective in termination at the end of the M gene. Efficient M gene termination could be restored to the mutant Rep 22 template in either of two ways: by increasing the U tract length from four to six residues or by restoring a G residue immediately downstream of the wild-type (WT) U4 tract. In a dicistronic SH-HN minigenome, a U4-G combination was functionally equivalent to the naturally occurring SH U6-A gene end in directing SH transcription termination. In addition to affecting termination, the M-F intergenic region also influenced polymerase reinitiation. In the context of the WT U4-G M gene end, substituting nonviral sequences into the M-F intergenic region had a differential effect on F gene reinitiation, where some but not all nonviral sequences inhibited reinitiation. The inhibition of F gene reinitiation correlated with foreign sequences having a high C content. Deleting 6 bases or inserting 18 additional nucleotides into the middle of the 22-base M-F intergenic segment did not influence M gene termination or F gene reinitiation, indicating that M-F intergenic length per se is not a important factor modulating the SV5 polymerase activity. Our results suggest that the sequence diversity at an SV5 gene junction reflects specific combinations which may differentially affect SV5 gene expression and provide an additional level of transcriptional control beyond that which results from the distance of a gene from the 3' end promoter.  (+info)

Structural basis for paramyxovirus-mediated membrane fusion. (7/1579)

Paramyxoviruses are responsible for significant human mortality and disease worldwide, but the molecular mechanisms underlying their entry into host cells remain poorly understood. We have solved the crystal structure of a fragment of the simian parainfluenza virus 5 fusion protein (SV5 F), revealing a 96 A long coiled coil surrounded by three antiparallel helices. This structure places the fusion and transmembrane anchor of SV5 F in close proximity with a large intervening domain at the opposite end of the coiled coil. Six amino acids, potentially part of the fusion peptide, form a segment of the central coiled coil, suggesting that this structure extends into the membrane. Deletion mutants of SV5 F indicate that putative flexible tethers between the coiled coil and the viral membrane are dispensable for fusion. The lack of flexible tethers may couple a final conformational change in the F protein directly to the fusion of two bilayers.  (+info)

The hemagglutinin-esterase of mouse hepatitis virus strain S is a sialate-4-O-acetylesterase. (8/1579)

By comparative analysis of the hemagglutinin-esterase (HE) protein of mouse hepatitis virus strain S (MHV-S) and the HE protein of influenza C virus, we found major differences in substrate specificities. In striking contrast to the influenza C virus enzyme, the MHV-S esterase was unable to release acetate from bovine submandibulary gland mucin. Furthermore, MHV-S could not remove influenza C virus receptors from erythrocytes. Analysis with free sialic acid derivatives revealed that the MHV-S HE protein specifically de-O-acetylates 5-N-acetyl-4-O-acetyl sialic acid (Neu4, 5Ac2) but not 5-N-acetyl-9-O-acetyl sialic acid (Neu5,9Ac2), which is the major substrate for esterases of influenza C virus and bovine coronaviruses. In addition, the MHV-S esterase converted glycosidically bound Neu4,5Ac2 of guinea pig serum glycoproteins to Neu5Ac. By expression of the MHV esterase with recombinant vaccinia virus and incubation with guinea pig serum, we demonstrated that the viral HE possesses sialate-4-O-acetylesterase activity. In addition to observed enzymatic activity, MHV-S exhibited affinity to guinea pig and horse serum glycoproteins. Binding required sialate-4-O-acetyl groups and was abolished by chemical de-O-acetylation. Since Neu4,5Ac2 has not been identified in mice, the nature of potential substrates and/or secondary receptors for MHV-S in the natural host remains to be determined. The esterase of MHV-S is the first example of a viral enzyme with high specificity and affinity toward 4-O-acetylated sialic acids.  (+info)

Viral fusion proteins are specialized surface proteins found on the envelope of enveloped viruses. These proteins play a crucial role in the viral infection process by mediating the fusion of the viral membrane with the target cell membrane, allowing the viral genetic material to enter the host cell and initiate replication.

The fusion protein is often synthesized as an inactive precursor, which undergoes a series of conformational changes upon interaction with specific receptors on the host cell surface. This results in the exposure of hydrophobic fusion peptides or domains that insert into the target cell membrane, bringing the two membranes into close proximity and facilitating their merger.

A well-known example of a viral fusion protein is the gp120/gp41 complex found on the Human Immunodeficiency Virus (HIV). The gp120 subunit binds to CD4 receptors and chemokine coreceptors on the host cell surface, triggering conformational changes in the gp41 subunit that expose the fusion peptide and enable membrane fusion. Understanding the structure and function of viral fusion proteins is important for developing antiviral strategies and vaccines.

Membrane fusion is a fundamental biological process that involves the merging of two initially separate lipid bilayers, such as those surrounding cells or organelles, to form a single continuous membrane. This process plays a crucial role in various physiological events including neurotransmitter release, hormone secretion, fertilization, viral infection, and intracellular trafficking of proteins and lipids. Membrane fusion is tightly regulated and requires the participation of specific proteins called SNAREs (Soluble NSF Attachment Protein REceptors) and other accessory factors that facilitate the recognition, approximation, and merger of the membranes. The energy required to overcome the repulsive forces between the negatively charged lipid headgroups is provided by these proteins, which undergo conformational changes during the fusion process. Membrane fusion is a highly specific and coordinated event, ensuring that the correct membranes fuse at the right time and place within the cell.

Virus internalization, also known as viral entry, is the process by which a virus enters a host cell to infect it and replicate its genetic material. This process typically involves several steps:

1. Attachment: The viral envelope proteins bind to specific receptors on the surface of the host cell.
2. Entry: The virus then enters the host cell through endocytosis or membrane fusion, depending on the type of virus.
3. Uncoating: Once inside the host cell, the viral capsid is removed, releasing the viral genome into the cytoplasm.
4. Replication: The viral genome then uses the host cell's machinery to replicate itself and produce new viral particles.

It's important to note that the specific mechanisms of virus internalization can vary widely between different types of viruses, and are an active area of research in virology and infectious disease.

Recombinant fusion proteins are artificially created biomolecules that combine the functional domains or properties of two or more different proteins into a single protein entity. They are generated through recombinant DNA technology, where the genes encoding the desired protein domains are linked together and expressed as a single, chimeric gene in a host organism, such as bacteria, yeast, or mammalian cells.

The resulting fusion protein retains the functional properties of its individual constituent proteins, allowing for novel applications in research, diagnostics, and therapeutics. For instance, recombinant fusion proteins can be designed to enhance protein stability, solubility, or immunogenicity, making them valuable tools for studying protein-protein interactions, developing targeted therapies, or generating vaccines against infectious diseases or cancer.

Examples of recombinant fusion proteins include:

1. Etaglunatide (ABT-523): A soluble Fc fusion protein that combines the heavy chain fragment crystallizable region (Fc) of an immunoglobulin with the extracellular domain of the human interleukin-6 receptor (IL-6R). This fusion protein functions as a decoy receptor, neutralizing IL-6 and its downstream signaling pathways in rheumatoid arthritis.
2. Etanercept (Enbrel): A soluble TNF receptor p75 Fc fusion protein that binds to tumor necrosis factor-alpha (TNF-α) and inhibits its proinflammatory activity, making it a valuable therapeutic option for treating autoimmune diseases like rheumatoid arthritis, ankylosing spondylitis, and psoriasis.
3. Abatacept (Orencia): A fusion protein consisting of the extracellular domain of cytotoxic T-lymphocyte antigen 4 (CTLA-4) linked to the Fc region of an immunoglobulin, which downregulates T-cell activation and proliferation in autoimmune diseases like rheumatoid arthritis.
4. Belimumab (Benlysta): A monoclonal antibody that targets B-lymphocyte stimulator (BLyS) protein, preventing its interaction with the B-cell surface receptor and inhibiting B-cell activation in systemic lupus erythematosus (SLE).
5. Romiplostim (Nplate): A fusion protein consisting of a thrombopoietin receptor agonist peptide linked to an immunoglobulin Fc region, which stimulates platelet production in patients with chronic immune thrombocytopenia (ITP).
6. Darbepoetin alfa (Aranesp): A hyperglycosylated erythropoiesis-stimulating protein that functions as a longer-acting form of recombinant human erythropoietin, used to treat anemia in patients with chronic kidney disease or cancer.
7. Palivizumab (Synagis): A monoclonal antibody directed against the F protein of respiratory syncytial virus (RSV), which prevents RSV infection and is administered prophylactically to high-risk infants during the RSV season.
8. Ranibizumab (Lucentis): A recombinant humanized monoclonal antibody fragment that binds and inhibits vascular endothelial growth factor A (VEGF-A), used in the treatment of age-related macular degeneration, diabetic retinopathy, and other ocular disorders.
9. Cetuximab (Erbitux): A chimeric monoclonal antibody that binds to epidermal growth factor receptor (EGFR), used in the treatment of colorectal cancer and head and neck squamous cell carcinoma.
10. Adalimumab (Humira): A fully humanized monoclonal antibody that targets tumor necrosis factor-alpha (TNF-α), used in the treatment of various inflammatory diseases, including rheumatoid arthritis, psoriasis, and Crohn's disease.
11. Bevacizumab (Avastin): A recombinant humanized monoclonal antibody that binds to VEGF-A, used in the treatment of various cancers, including colorectal, lung, breast, and kidney cancer.
12. Trastuzumab (Herceptin): A humanized monoclonal antibody that targets HER2/neu receptor, used in the treatment of breast cancer.
13. Rituximab (Rituxan): A chimeric monoclonal antibody that binds to CD20 antigen on B cells, used in the treatment of non-Hodgkin's lymphoma and rheumatoid arthritis.
14. Palivizumab (Synagis): A humanized monoclonal antibody that binds to the F protein of respiratory syncytial virus, used in the prevention of respiratory syncytial virus infection in high-risk infants.
15. Infliximab (Remicade): A chimeric monoclonal antibody that targets TNF-α, used in the treatment of various inflammatory diseases, including Crohn's disease, ulcerative colitis, rheumatoid arthritis, and ankylosing spondylitis.
16. Natalizumab (Tysabri): A humanized monoclonal antibody that binds to α4β1 integrin, used in the treatment of multiple sclerosis and Crohn's disease.
17. Adalimumab (Humira): A fully human monoclonal antibody that targets TNF-α, used in the treatment of various inflammatory diseases, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn's disease, and ulcerative colitis.
18. Golimumab (Simponi): A fully human monoclonal antibody that targets TNF-α, used in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ulcerative colitis.
19. Certolizumab pegol (Cimzia): A PEGylated Fab' fragment of a humanized monoclonal antibody that targets TNF-α, used in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and Crohn's disease.
20. Ustekinumab (Stelara): A fully human monoclonal antibody that targets IL-12 and IL-23, used in the treatment of psoriasis, psoriatic arthritis, and Crohn's disease.
21. Secukinumab (Cosentyx): A fully human monoclonal antibody that targets IL-17A, used in the treatment of psoriasis, psoriatic arthritis, and ankylosing spondylitis.
22. Ixekizumab (Taltz): A fully human monoclonal antibody that targets IL-17A, used in the treatment of psoriasis and psoriatic arthritis.
23. Brodalumab (Siliq): A fully human monoclonal antibody that targets IL-17 receptor A, used in the treatment of psoriasis.
24. Sarilumab (Kevzara): A fully human monoclonal antibody that targets the IL-6 receptor, used in the treatment of rheumatoid arthritis.
25. Tocilizumab (Actemra): A humanized monoclonal antibody that targets the IL-6 receptor, used in the treatment of rheumatoid arthritis, systemic juvenile idiopathic arthritis, polyarticular juvenile idiopathic arthritis, giant cell arteritis, and chimeric antigen receptor T-cell-induced cytokine release syndrome.
26. Siltuximab (Sylvant): A chimeric monoclonal antibody that targets IL-6, used in the treatment of multicentric Castleman disease.
27. Satralizumab (Enspryng): A humanized monoclonal antibody that targets IL-6 receptor alpha, used in the treatment of neuromyelitis optica spectrum disorder.
28. Sirukumab (Plivensia): A human monoclonal antibody that targets IL-6, used in the treatment

Cell fusion is the process by which two or more cells combine to form a single cell with a single nucleus, containing the genetic material from all of the original cells. This can occur naturally in certain biological processes, such as fertilization (when a sperm and egg cell fuse to form a zygote), muscle development (where multiple muscle precursor cells fuse together to create multinucleated muscle fibers), and during the formation of bone (where osteoclasts, the cells responsible for breaking down bone tissue, are multinucleated).

Cell fusion can also be induced artificially in laboratory settings through various methods, including chemical treatments, electrical stimulation, or viral vectors. Induced cell fusion is often used in research to create hybrid cells with unique properties, such as cybrid cells (cytoplasmic hybrids) and heterokaryons (nuclear hybrids). These hybrid cells can help scientists study various aspects of cell biology, genetics, and disease mechanisms.

In summary, cell fusion is the merging of two or more cells into one, resulting in a single cell with combined genetic material. This process occurs naturally during certain biological processes and can be induced artificially for research purposes.

Viral envelope proteins are structural proteins found in the envelope that surrounds many types of viruses. These proteins play a crucial role in the virus's life cycle, including attachment to host cells, fusion with the cell membrane, and entry into the host cell. They are typically made up of glycoproteins and are often responsible for eliciting an immune response in the host organism. The exact structure and function of viral envelope proteins vary between different types of viruses.

Tick-borne encephalitis (TBE) viruses are a group of related viruses that are primarily transmitted to humans through the bite of infected ticks. The main strains of TBE viruses include:

1. European tick-borne encephalitis virus (TBEV-Eu): This strain is found mainly in Europe and causes the majority of human cases of TBE. It is transmitted by the tick species Ixodes ricinus.
2. Siberian tick-borne encephalitis virus (TBEV-Sib): This strain is prevalent in Russia, Mongolia, and China, and is transmitted by the tick species Ixodes persulcatus.
3. Far Eastern tick-borne encephalitis virus (TBEV-FE): Also known as Russian spring-summer encephalitis (RSSE) virus, this strain is found in Russia, China, and Japan, and is transmitted by the tick species Ixodes persulcatus.
4. Louping ill virus (LIV): This strain is primarily found in the United Kingdom, Ireland, Portugal, and Spain, and is transmitted by the tick species Ixodes ricinus. It mainly affects sheep but can also infect humans.
5. Turkish sheep encephalitis virus (TSEV): This strain is found in Turkey and Greece and is primarily associated with ovine encephalitis, although it can occasionally cause human disease.
6. Negishi virus (NGS): This strain has been identified in Japan and Russia, but its role in human disease remains unclear.

TBE viruses are members of the Flaviviridae family and are closely related to other mosquito-borne flaviviruses such as West Nile virus, dengue virus, and Zika virus. The incubation period for TBE is usually 7-14 days after a tick bite, but it can range from 2 to 28 days. Symptoms of TBE include fever, headache, muscle pain, fatigue, and vomiting, followed by neurological symptoms such as meningitis (inflammation of the membranes surrounding the brain and spinal cord) or encephalitis (inflammation of the brain). Severe cases can lead to long-term complications or even death. No specific antiviral treatment is available for TBE, and management typically involves supportive care. Prevention measures include avoiding tick-infested areas, using insect repellents, wearing protective clothing, and promptly removing attached ticks. Vaccination is also recommended for individuals at high risk of exposure to TBE viruses.

A spike glycoprotein in coronaviruses is a type of protein that extends from the surface of the virus and gives it its characteristic crown-like appearance (hence the name "corona," which is Latin for "crown"). This protein plays a crucial role in the infection process of the virus. It allows the virus to attach to and enter specific cells in the host organism, typically through binding to a receptor on the cell surface. In the case of SARS-CoV-2, the coronavirus responsible for COVID-19, the spike protein binds to the angiotensin-converting enzyme 2 (ACE2) receptor found on cells in various tissues, including the lungs, heart, and gastrointestinal tract.

The spike protein is composed of two subunits: S1 and S2. The S1 subunit contains the receptor-binding domain (RBD), which recognizes and binds to the host cell receptor. After binding, the S2 subunit mediates the fusion of the viral membrane with the host cell membrane, allowing the viral genome to enter the host cell and initiate infection.

The spike protein is also a primary target for neutralizing antibodies generated by the host immune system during infection or following vaccination. Neutralizing antibodies bind to specific regions of the spike protein, preventing it from interacting with host cell receptors and thus inhibiting viral entry into cells.

In summary, a spike glycoprotein in coronaviruses is a crucial structural and functional component that facilitates viral attachment, fusion, and entry into host cells. Its importance in the infection process makes it an essential target for vaccine development and therapeutic interventions.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Giant cells are large, multinucleated cells that result from the fusion of monocytes or macrophages. They can be found in various types of inflammatory and degenerative lesions, including granulomas, which are a hallmark of certain diseases such as tuberculosis and sarcoidosis. There are several types of giant cells, including:

1. Langhans giant cells: These have a horseshoe-shaped or crescentic arrangement of nuclei around the periphery of the cell. They are typically found in granulomas associated with infectious diseases such as tuberculosis and histoplasmosis.
2. Foreign body giant cells: These form in response to the presence of foreign material, such as a splinter or suture, in tissue. The nuclei are usually scattered throughout the cell cytoplasm.
3. Touton giant cells: These are found in certain inflammatory conditions, such as xanthomatosis and granulomatous slack skin. They have a central core of lipid-laden histiocytes surrounded by a ring of nuclei.
4. Osteoclast giant cells: These are multinucleated cells responsible for bone resorption. They can be found in conditions such as giant cell tumors of bone and Paget's disease.

It is important to note that the presence of giant cells alone does not necessarily indicate a specific diagnosis, and their significance must be interpreted within the context of the overall clinical and pathological findings.

Liposomes are artificially prepared, small, spherical vesicles composed of one or more lipid bilayers that enclose an aqueous compartment. They can encapsulate both hydrophilic and hydrophobic drugs, making them useful for drug delivery applications in the medical field. The lipid bilayer structure of liposomes is similar to that of biological membranes, which allows them to merge with and deliver their contents into cells. This property makes liposomes a valuable tool in delivering drugs directly to targeted sites within the body, improving drug efficacy while minimizing side effects.

Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.

Vero cells are a line of cultured kidney epithelial cells that were isolated from an African green monkey (Cercopithecus aethiops) in the 1960s. They are named after the location where they were initially developed, the Vervet Research Institute in Japan.

Vero cells have the ability to divide indefinitely under certain laboratory conditions and are often used in scientific research, including virology, as a host cell for viruses to replicate. This allows researchers to study the characteristics of various viruses, such as their growth patterns and interactions with host cells. Vero cells are also used in the production of some vaccines, including those for rabies, polio, and Japanese encephalitis.

It is important to note that while Vero cells have been widely used in research and vaccine production, they can still have variations between different cell lines due to factors like passage number or culture conditions. Therefore, it's essential to specify the exact source and condition of Vero cells when reporting experimental results.

'Cercopithecus aethiops' is the scientific name for the monkey species more commonly known as the green monkey. It belongs to the family Cercopithecidae and is native to western Africa. The green monkey is omnivorous, with a diet that includes fruits, nuts, seeds, insects, and small vertebrates. They are known for their distinctive greenish-brown fur and long tail. Green monkeys are also important animal models in biomedical research due to their susceptibility to certain diseases, such as SIV (simian immunodeficiency virus), which is closely related to HIV.

Tertiary protein structure refers to the three-dimensional arrangement of all the elements (polypeptide chains) of a single protein molecule. It is the highest level of structural organization and results from interactions between various side chains (R groups) of the amino acids that make up the protein. These interactions, which include hydrogen bonds, ionic bonds, van der Waals forces, and disulfide bridges, give the protein its unique shape and stability, which in turn determines its function. The tertiary structure of a protein can be stabilized by various factors such as temperature, pH, and the presence of certain ions. Any changes in these factors can lead to denaturation, where the protein loses its tertiary structure and thus its function.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

Severe Acute Respiratory Syndrome (SARS) is a viral respiratory illness caused by the SARS coronavirus (SARS-CoV). This virus is a member of the Coronaviridae family and is thought to be transmitted most readily through close person-to-person contact via respiratory droplets produced when an infected person coughs or sneezes.

The SARS outbreak began in southern China in 2002 and spread to several other countries before it was contained. The illness causes symptoms such as fever, chills, and body aches, which progress to a dry cough and sometimes pneumonia. Some people also report diarrhea. In severe cases, the illness can cause respiratory failure or death.

It's important to note that SARS is not currently a global health concern, as there have been no known cases since 2004. However, it remains a significant example of how quickly and widely a new infectious disease can spread in today's interconnected world.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

Peptides are short chains of amino acid residues linked by covalent bonds, known as peptide bonds. They are formed when two or more amino acids are joined together through a condensation reaction, which results in the elimination of a water molecule and the formation of an amide bond between the carboxyl group of one amino acid and the amino group of another.

Peptides can vary in length from two to about fifty amino acids, and they are often classified based on their size. For example, dipeptides contain two amino acids, tripeptides contain three, and so on. Oligopeptides typically contain up to ten amino acids, while polypeptides can contain dozens or even hundreds of amino acids.

Peptides play many important roles in the body, including serving as hormones, neurotransmitters, enzymes, and antibiotics. They are also used in medical research and therapeutic applications, such as drug delivery and tissue engineering.

Secondary protein structure refers to the local spatial arrangement of amino acid chains in a protein, typically described as regular repeating patterns held together by hydrogen bonds. The two most common types of secondary structures are the alpha-helix (α-helix) and the beta-pleated sheet (β-sheet). In an α-helix, the polypeptide chain twists around itself in a helical shape, with each backbone atom forming a hydrogen bond with the fourth amino acid residue along the chain. This forms a rigid rod-like structure that is resistant to bending or twisting forces. In β-sheets, adjacent segments of the polypeptide chain run parallel or antiparallel to each other and are connected by hydrogen bonds, forming a pleated sheet-like arrangement. These secondary structures provide the foundation for the formation of tertiary and quaternary protein structures, which determine the overall three-dimensional shape and function of the protein.

Membrane glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide backbone. They are integral components of biological membranes, spanning the lipid bilayer and playing crucial roles in various cellular processes.

The glycosylation of these proteins occurs in the endoplasmic reticulum (ER) and Golgi apparatus during protein folding and trafficking. The attached glycans can vary in structure, length, and composition, which contributes to the diversity of membrane glycoproteins.

Membrane glycoproteins can be classified into two main types based on their orientation within the lipid bilayer:

1. Type I (N-linked): These glycoproteins have a single transmembrane domain and an extracellular N-terminus, where the oligosaccharides are predominantly attached via asparagine residues (Asn-X-Ser/Thr sequon).
2. Type II (C-linked): These glycoproteins possess two transmembrane domains and an intracellular C-terminus, with the oligosaccharides linked to tryptophan residues via a mannose moiety.

Membrane glycoproteins are involved in various cellular functions, such as:

* Cell adhesion and recognition
* Receptor-mediated signal transduction
* Enzymatic catalysis
* Transport of molecules across membranes
* Cell-cell communication
* Immunological responses

Some examples of membrane glycoproteins include cell surface receptors (e.g., growth factor receptors, cytokine receptors), adhesion molecules (e.g., integrins, cadherins), and transporters (e.g., ion channels, ABC transporters).

Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.

Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as α-helices and β-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.

Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.

A cell membrane, also known as the plasma membrane, is a thin semi-permeable phospholipid bilayer that surrounds all cells in animals, plants, and microorganisms. It functions as a barrier to control the movement of substances in and out of the cell, allowing necessary molecules such as nutrients, oxygen, and signaling molecules to enter while keeping out harmful substances and waste products. The cell membrane is composed mainly of phospholipids, which have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails. This unique structure allows the membrane to be flexible and fluid, yet selectively permeable. Additionally, various proteins are embedded in the membrane that serve as channels, pumps, receptors, and enzymes, contributing to the cell's overall functionality and communication with its environment.

HIV Envelope Protein gp41 is a transmembrane protein that forms a part of the HIV envelope complex. It plays a crucial role in the viral fusion process, where it helps the virus to enter and infect the host cell. The "gp" stands for glycoprotein, indicating that the protein contains carbohydrate chains. The number 41 refers to its molecular weight, which is approximately 41 kilodaltons.

The gp41 protein exists as a trimer on the surface of the viral envelope and interacts with the host cell membrane during viral entry. It contains several functional domains, including an N-terminal fusion peptide, two heptad repeat regions (HR1 and HR2), a transmembrane domain, and a cytoplasmic tail. During viral fusion, the gp41 protein undergoes significant conformational changes, allowing the fusion peptide to insert into the host cell membrane. The HR1 and HR2 regions then interact to form a six-helix bundle structure, which brings the viral and host cell membranes together, facilitating membrane fusion and viral entry.

The gp41 protein is an important target for HIV vaccine development and antiretroviral therapy. Neutralizing antibodies that recognize and bind to specific epitopes on the gp41 protein can prevent viral entry and infection, while small molecule inhibitors that interfere with the formation of the six-helix bundle structure can also block viral fusion and replication.

Paramyxovirinae is a subfamily of viruses in the family Paramyxoviridae, order Mononegavirales. These viruses are enveloped, negative-sense, single-stranded RNA viruses that cause various diseases in animals and humans. The subfamily includes several important human pathogens such as:

1. Respiratory syncytial virus (RSV): A major cause of respiratory tract infections in infants, young children, and older adults.
2. Human metapneumovirus (HMPV): Another common cause of respiratory illness, particularly in children.
3. Parainfluenza viruses (PIVs): Responsible for upper and lower respiratory tract infections, including croup, bronchitis, and pneumonia.
4. Mumps virus: Causes the infectious disease mumps, characterized by swelling of the salivary glands.
5. Measles virus: A highly contagious virus that causes measles, a serious respiratory illness with characteristic rash.
6. Hendra virus and Nipah virus: Zoonotic viruses that can cause severe respiratory and neurological diseases in humans and animals.

These viruses share common structural and genetic features, such as an enveloped virion with a helical nucleocapsid, and a genome consisting of non-segmented, negative-sense single-stranded RNA. They also utilize similar replication strategies and have related gene arrangements.

An oncogene protein fusion is a result of a genetic alteration in which parts of two different genes combine to create a hybrid gene that can contribute to the development of cancer. This fusion can lead to the production of an abnormal protein that promotes uncontrolled cell growth and division, ultimately resulting in a malignant tumor. Oncogene protein fusions are often caused by chromosomal rearrangements such as translocations, inversions, or deletions and are commonly found in various types of cancer, including leukemia and sarcoma. These genetic alterations can serve as potential targets for cancer diagnosis and therapy.

A gene fusion, also known as a chromosomal translocation or fusion gene, is an abnormal genetic event where parts of two different genes combine to create a single, hybrid gene. This can occur due to various mechanisms such as chromosomal rearrangements, deletions, or inversions, leading to the formation of a chimeric gene with new and often altered functions.

Gene fusions can result in the production of abnormal fusion proteins that may contribute to cancer development and progression by promoting cell growth, inhibiting apoptosis (programmed cell death), or activating oncogenic signaling pathways. In some cases, gene fusions are specific to certain types of cancer and serve as valuable diagnostic markers and therapeutic targets for personalized medicine.

Spinal fusion is a surgical procedure where two or more vertebrae in the spine are fused together to create a solid bone. The purpose of this procedure is to restrict movement between the fused vertebrae, which can help reduce pain and stabilize the spine. This is typically done using bone grafts or bone graft substitutes, along with hardware such as rods, screws, or cages to hold the vertebrae in place while they heal together. The procedure may be recommended for various spinal conditions, including degenerative disc disease, spinal stenosis, spondylolisthesis, scoliosis, or fractures.

Hemagglutinins are glycoprotein spikes found on the surface of influenza viruses. They play a crucial role in the viral infection process by binding to sialic acid receptors on host cells, primarily in the respiratory tract. After attachment, hemagglutinins mediate the fusion of the viral and host cell membranes, allowing the viral genome to enter the host cell and initiate replication.

There are 18 different subtypes of hemagglutinin (H1-H18) identified in influenza A viruses, which naturally infect various animal species, including birds, pigs, and humans. The specificity of hemagglutinins for particular sialic acid receptors can influence host range and tissue tropism, contributing to the zoonotic potential of certain influenza A virus subtypes.

Hemagglutination inhibition (HI) assays are commonly used in virology and epidemiology to measure the antibody response to influenza viruses and determine vaccine effectiveness. In these assays, hemagglutinins bind to red blood cells coated with sialic acid receptors, forming a diffuse mat of cells that can be observed visually. The addition of specific antisera containing antibodies against the hemagglutinin prevents this binding and results in the formation of discrete buttons of red blood cells, indicating a positive HI titer and the presence of neutralizing antibodies.

I'm sorry for any confusion, but "HN protein" is not a widely recognized or established medical term. HN is an abbreviation commonly used in virology to refer to the hemagglutinin-neuraminidase protein found on the surface of certain viruses, such as the paramyxoviridae family which includes viruses like parainfluenza and Hendra virus.

The HN protein plays a crucial role in the virus's ability to infect host cells. It helps the virus attach to and enter the host cell, and also assists in the release of new virus particles from infected cells. However, without more specific context, it's difficult to provide a more precise definition of "HN protein." If you have more details about the context in which this term was used, I'd be happy to try to provide a more specific answer.

Hemagglutinin (HA) glycoproteins are surface proteins found on influenza viruses. They play a crucial role in the virus's ability to infect and spread within host organisms.

The HAs are responsible for binding to sialic acid receptors on the host cell's surface, allowing the virus to attach and enter the cell. After endocytosis, the viral and endosomal membranes fuse, releasing the viral genome into the host cell's cytoplasm.

There are several subtypes of hemagglutinin (H1-H18) identified so far, with H1, H2, and H3 being common in human infections. The significant antigenic differences among these subtypes make them important targets for the development of influenza vaccines. However, due to their high mutation rate, new vaccine formulations are often required to match the circulating virus strains.

In summary, hemagglutinin glycoproteins on influenza viruses are essential for host cell recognition and entry, making them important targets for diagnosis, prevention, and treatment of influenza infections.

Respirovirus is not typically used as a formal medical term in modern taxonomy. However, historically, it was used to refer to a genus of viruses within the family Paramyxoviridae, order Mononegavirales. This genus included several important human and animal pathogens that cause respiratory infections.

Human respiroviruses include:
1. Human parainfluenza virus (HPIV) types 1, 2, and 3: These viruses are a common cause of upper and lower respiratory tract infections, such as croup, bronchitis, and pneumonia, particularly in young children.
2. Sendai virus (also known as murine respirovirus): This virus primarily infects rodents but can occasionally cause mild respiratory illness in humans, especially those who work closely with these animals.

The term "respirovirus" is not officially recognized by the International Committee on Taxonomy of Viruses (ICTV) anymore, and these viruses are now classified under different genera within the subfamily Pneumovirinae: Human parainfluenza viruses 1 and 3 belong to the genus Orthorubulavirus, while Human parainfluenza virus 2 is placed in the genus Metapneumovirus.

HIV Fusion Inhibitors are a type of antiretroviral medication used in the treatment and management of HIV infection. They work by preventing the virus from entering and infecting CD4 cells, which are a type of white blood cell that plays a crucial role in the body's immune response.

Fusion inhibitors bind to the gp41 protein on the surface of the HIV envelope, preventing it from undergoing conformational changes necessary for fusion with the host cell membrane. This inhibits the virus from entering and infecting the CD4 cells, thereby reducing the viral load in the body and slowing down the progression of the disease.

Examples of HIV Fusion Inhibitors include enfuvirtide (T-20) and ibalizumab (TMB-355). These medications are usually used in combination with other antiretroviral drugs as part of a highly active antiretroviral therapy (HAART) regimen. It's important to note that HIV fusion inhibitors must be administered parenterally, typically by injection, due to their large size and poor oral bioavailability.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Virus receptors are specific molecules (commonly proteins) on the surface of host cells that viruses bind to in order to enter and infect those cells. This interaction between the virus and its receptor is a critical step in the infection process. Different types of viruses have different receptor requirements, and identifying these receptors can provide important insights into the biology of the virus and potential targets for antiviral therapies.

Membrane fusion proteins are specialized protein molecules that play a critical role in the process of membrane fusion, which is a fundamental biological event that allows for the merging of two separate lipid bilayers to form a single continuous membrane. This process is essential for various cellular functions such as exocytosis, endocytosis, neurotransmitter release, viral entry into host cells, and fertilization.

In membrane fusion, membrane fusion proteins undergo conformational changes that bring the two membranes into close proximity, allowing for non-covalent interactions between lipid molecules to overcome their natural repulsion and merge the membranes. The most well-studied membrane fusion proteins are found in the SNARE (Soluble NSF Attachment Protein REceptor) family, which includes both vesicle (v-) SNAREs and target (t-) SNAREs. These proteins interact in a highly specific manner to form a tight complex that brings the vesicle and target membranes together, ultimately leading to fusion.

Membrane fusion proteins can also be classified based on their location within the cell. For example, some are located in the plasma membrane, while others are found in intracellular organelles such as endosomes, lysosomes, and the Golgi apparatus. Additionally, there are viral membrane fusion proteins that facilitate the entry of enveloped viruses into host cells by mediating the fusion of the viral envelope with the host cell membrane.

Overall, membrane fusion proteins are crucial for maintaining normal cellular function and are involved in a wide range of physiological processes, as well as various disease states such as neurodegenerative disorders and viral infections.

Parainfluenza Virus 1, Human (HPIV-1) is a type of respiratory virus that belongs to the family Paramyxoviridae and genus Respirovirus. It is one of the four serotypes of human parainfluenza viruses (HPIVs), which are important causes of acute respiratory infections in children, immunocompromised individuals, and the elderly.

HPIV-1 primarily infects the upper respiratory tract, causing symptoms such as cough, runny nose, sore throat, and fever. However, it can also cause lower respiratory tract infections, including bronchitis, bronchiolitis, and pneumonia, particularly in young children and infants.

HPIV-1 is transmitted through respiratory droplets or direct contact with infected individuals. The incubation period for HPIV-1 infection ranges from 2 to 7 days, after which symptoms can last for up to 10 days. There is no specific antiviral treatment available for HPIV-1 infections, and management typically involves supportive care such as hydration, fever reduction, and respiratory support if necessary.

Prevention measures include good hand hygiene, avoiding close contact with infected individuals, and practicing cough etiquette. Vaccines are not currently available for HPIV-1 infections, but research is ongoing to develop effective vaccines against these viruses.

Cricetinae is a subfamily of rodents that includes hamsters, gerbils, and relatives. These small mammals are characterized by having short limbs, compact bodies, and cheek pouches for storing food. They are native to various parts of the world, particularly in Europe, Asia, and Africa. Some species are popular pets due to their small size, easy care, and friendly nature. In a medical context, understanding the biology and behavior of Cricetinae species can be important for individuals who keep them as pets or for researchers studying their physiology.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Green Fluorescent Protein (GFP) is not a medical term per se, but a scientific term used in the field of molecular biology. GFP is a protein that exhibits bright green fluorescence when exposed to light, particularly blue or ultraviolet light. It was originally discovered in the jellyfish Aequorea victoria.

In medical and biological research, scientists often use recombinant DNA technology to introduce the gene for GFP into other organisms, including bacteria, plants, and animals, including humans. This allows them to track the expression and localization of specific genes or proteins of interest in living cells, tissues, or even whole organisms.

The ability to visualize specific cellular structures or processes in real-time has proven invaluable for a wide range of research areas, from studying the development and function of organs and organ systems to understanding the mechanisms of diseases and the effects of therapeutic interventions.

A lipid bilayer is a thin membrane made up of two layers of lipid molecules, primarily phospholipids. The hydrophilic (water-loving) heads of the lipids face outwards, coming into contact with watery environments on both sides, while the hydrophobic (water-fearing) tails point inward, away from the aqueous surroundings. This unique structure allows lipid bilayers to form a stable barrier that controls the movement of molecules and ions in and out of cells and organelles, thus playing a crucial role in maintaining cellular compartmentalization and homeostasis.

Amino acid repetitive sequences refer to patterns of amino acids that are repeated in a polypeptide chain. These repetitions can vary in length and can be composed of a single type of amino acid or a combination of different types. In some cases, expansions of these repetitive sequences can lead to the production of abnormal proteins that are associated with certain genetic disorders. The expansion of trinucleotide repeats that code for particular amino acids is one example of this phenomenon. These expansions can result in protein misfolding and aggregation, leading to neurodegenerative diseases such as Huntington's disease and spinocerebellar ataxias.

A virion is the complete, infectious form of a virus outside its host cell. It consists of the viral genome (DNA or RNA) enclosed within a protein coat called the capsid, which is often surrounded by a lipid membrane called the envelope. The envelope may contain viral proteins and glycoproteins that aid in attachment to and entry into host cells during infection. The term "virion" emphasizes the infectious nature of the virus particle, as opposed to non-infectious components like individual capsid proteins or naked viral genome.

Luminescent proteins are a type of protein that emit light through a chemical reaction, rather than by absorbing and re-emitting light like fluorescent proteins. This process is called bioluminescence. The light emitted by luminescent proteins is often used in scientific research as a way to visualize and track biological processes within cells and organisms.

One of the most well-known luminescent proteins is Green Fluorescent Protein (GFP), which was originally isolated from jellyfish. However, GFP is actually a fluorescent protein, not a luminescent one. A true example of a luminescent protein is the enzyme luciferase, which is found in fireflies and other bioluminescent organisms. When luciferase reacts with its substrate, luciferin, it produces light through a process called oxidation.

Luminescent proteins have many applications in research, including as reporters for gene expression, as markers for protein-protein interactions, and as tools for studying the dynamics of cellular processes. They are also used in medical imaging and diagnostics, as well as in the development of new therapies.

Orthomyxoviridae is a family of viruses that includes influenza A, B, and C viruses, which are the causative agents of flu in humans and animals. These viruses are enveloped, meaning they have a lipid membrane derived from the host cell, and have a single-stranded, negative-sense RNA genome. The genome is segmented, meaning it consists of several separate pieces of RNA, which allows for genetic reassortment or "shuffling" when two different strains infect the same cell, leading to the emergence of new strains.

The viral envelope contains two major glycoproteins: hemagglutinin (HA) and neuraminidase (NA). The HA protein is responsible for binding to host cells and facilitating entry into the cell, while NA helps release newly formed virus particles from infected cells by cleaving sialic acid residues on the host cell surface.

Orthomyxoviruses are known to cause respiratory infections in humans and animals, with influenza A viruses being the most virulent and capable of causing pandemics. Influenza B viruses typically cause less severe illness and are primarily found in humans, while influenza C viruses generally cause mild upper respiratory symptoms and are also mainly restricted to humans.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Semliki Forest Virus (SFV) is an alphavirus in the Togaviridae family, which is primarily transmitted to vertebrates through mosquito vectors. The virus was initially isolated from mosquitoes in the Semliki Forest of Uganda and has since been found in various parts of Africa and Asia. SFV infection in humans can cause a mild febrile illness characterized by fever, headache, muscle pain, and rash. However, it is more commonly known for causing severe disease in animals, particularly non-human primates and cattle, where it can lead to encephalitis or hemorrhagic fever. SFV has also been used as a model organism in laboratory studies of virus replication and pathogenesis.

A virus is a small infectious agent that replicates inside the living cells of an organism. It is not considered to be a living organism itself, as it lacks the necessary components to independently maintain its own metabolic functions. Viruses are typically composed of genetic material, either DNA or RNA, surrounded by a protein coat called a capsid. Some viruses also have an outer lipid membrane known as an envelope.

Viruses can infect all types of organisms, from animals and plants to bacteria and archaea. They cause various diseases by invading the host cell, hijacking its machinery, and using it to produce numerous copies of themselves, which can then infect other cells. The resulting infection and the immune response it triggers can lead to a range of symptoms, depending on the virus and the host organism.

Viruses are transmitted through various means, such as respiratory droplets, bodily fluids, contaminated food or water, and vectors like insects. Prevention methods include vaccination, practicing good hygiene, using personal protective equipment, and implementing public health measures to control their spread.

HIV-1 (Human Immunodeficiency Virus type 1) is a species of the retrovirus genus that causes acquired immunodeficiency syndrome (AIDS). It is primarily transmitted through sexual contact, exposure to infected blood or blood products, and from mother to child during pregnancy, childbirth, or breastfeeding. HIV-1 infects vital cells in the human immune system, such as CD4+ T cells, macrophages, and dendritic cells, leading to a decline in their numbers and weakening of the immune response over time. This results in the individual becoming susceptible to various opportunistic infections and cancers that ultimately cause death if left untreated. HIV-1 is the most prevalent form of HIV worldwide and has been identified as the causative agent of the global AIDS pandemic.

Membrane lipids are the main component of biological membranes, forming a lipid bilayer in which various cellular processes take place. These lipids include phospholipids, glycolipids, and cholesterol. Phospholipids are the most abundant type, consisting of a hydrophilic head (containing a phosphate group) and two hydrophobic tails (composed of fatty acid chains). Glycolipids contain a sugar group attached to the lipid molecule. Cholesterol helps regulate membrane fluidity and permeability. Together, these lipids create a selectively permeable barrier that separates cells from their environment and organelles within cells.

Viral proteins are the proteins that are encoded by the viral genome and are essential for the viral life cycle. These proteins can be structural or non-structural and play various roles in the virus's replication, infection, and assembly process. Structural proteins make up the physical structure of the virus, including the capsid (the protein shell that surrounds the viral genome) and any envelope proteins (that may be present on enveloped viruses). Non-structural proteins are involved in the replication of the viral genome and modulation of the host cell environment to favor viral replication. Overall, a thorough understanding of viral proteins is crucial for developing antiviral therapies and vaccines.

In genetics, sequence alignment is the process of arranging two or more DNA, RNA, or protein sequences to identify regions of similarity or homology between them. This is often done using computational methods to compare the nucleotide or amino acid sequences and identify matching patterns, which can provide insight into evolutionary relationships, functional domains, or potential genetic disorders. The alignment process typically involves adjusting gaps and mismatches in the sequences to maximize the similarity between them, resulting in an aligned sequence that can be visually represented and analyzed.

Influenza A virus is defined as a negative-sense, single-stranded, segmented RNA virus belonging to the family Orthomyxoviridae. It is responsible for causing epidemic and pandemic influenza in humans and is also known to infect various animal species, such as birds, pigs, horses, and seals. The viral surface proteins, hemagglutinin (HA) and neuraminidase (NA), are the primary targets for antiviral drugs and vaccines. There are 18 different HA subtypes and 11 known NA subtypes, which contribute to the diversity and antigenic drift of Influenza A viruses. The zoonotic nature of this virus allows for genetic reassortment between human and animal strains, leading to the emergence of novel variants with pandemic potential.

HeLa cells are a type of immortalized cell line used in scientific research. They are derived from a cancer that developed in the cervical tissue of Henrietta Lacks, an African-American woman, in 1951. After her death, cells taken from her tumor were found to be capable of continuous division and growth in a laboratory setting, making them an invaluable resource for medical research.

HeLa cells have been used in a wide range of scientific studies, including research on cancer, viruses, genetics, and drug development. They were the first human cell line to be successfully cloned and are able to grow rapidly in culture, doubling their population every 20-24 hours. This has made them an essential tool for many areas of biomedical research.

It is important to note that while HeLa cells have been instrumental in numerous scientific breakthroughs, the story of their origin raises ethical questions about informed consent and the use of human tissue in research.

A peptide fragment is a short chain of amino acids that is derived from a larger peptide or protein through various biological or chemical processes. These fragments can result from the natural breakdown of proteins in the body during regular physiological processes, such as digestion, or they can be produced experimentally in a laboratory setting for research or therapeutic purposes.

Peptide fragments are often used in research to map the structure and function of larger peptides and proteins, as well as to study their interactions with other molecules. In some cases, peptide fragments may also have biological activity of their own and can be developed into drugs or diagnostic tools. For example, certain peptide fragments derived from hormones or neurotransmitters may bind to receptors in the body and mimic or block the effects of the full-length molecule.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Endosomes are membrane-bound compartments within eukaryotic cells that play a critical role in intracellular trafficking and sorting of various cargoes, including proteins and lipids. They are formed by the invagination of the plasma membrane during endocytosis, resulting in the internalization of extracellular material and cell surface receptors.

Endosomes can be classified into early endosomes, late endosomes, and recycling endosomes based on their morphology, molecular markers, and functional properties. Early endosomes are the initial sorting stations for internalized cargoes, where they undergo sorting and processing before being directed to their final destinations. Late endosomes are more acidic compartments that mature from early endosomes and are responsible for the transport of cargoes to lysosomes for degradation.

Recycling endosomes, on the other hand, are involved in the recycling of internalized cargoes back to the plasma membrane or to other cellular compartments. Endosomal sorting and trafficking are regulated by a complex network of molecular interactions involving various proteins, lipids, and intracellular signaling pathways.

Defects in endosomal function have been implicated in various human diseases, including neurodegenerative disorders, developmental abnormalities, and cancer. Therefore, understanding the mechanisms underlying endosomal trafficking and sorting is of great importance for developing therapeutic strategies to treat these conditions.

Antiviral agents are a class of medications that are designed to treat infections caused by viruses. Unlike antibiotics, which target bacteria, antiviral agents interfere with the replication and infection mechanisms of viruses, either by inhibiting their ability to replicate or by modulating the host's immune response to the virus.

Antiviral agents are used to treat a variety of viral infections, including influenza, herpes simplex virus (HSV) infections, human immunodeficiency virus (HIV) infection, hepatitis B and C, and respiratory syncytial virus (RSV) infections.

These medications can be administered orally, intravenously, or topically, depending on the type of viral infection being treated. Some antiviral agents are also used for prophylaxis, or prevention, of certain viral infections.

It is important to note that antiviral agents are not effective against all types of viruses and may have significant side effects. Therefore, it is essential to consult with a healthcare professional before starting any antiviral therapy.

Maltose-binding proteins (MBPs) are a type of protein that are capable of binding to maltose, a disaccharide made up of two glucose molecules. MBPs are found in many organisms, including bacteria and plants. In bacteria such as Escherichia coli, MBPs play a role in the transport and metabolism of maltose and maltodextrins, which are polymers of glucose.

MBPs are often used in laboratory research as model systems for studying protein folding and stability. They have a well-characterized three-dimensional structure and are relatively small, making them easy to produce and study. MBPs are also known for their high binding affinity and specificity for maltose, making them useful for purifying and detecting this sugar in various applications.

Circular dichroism (CD) is a technique used in physics and chemistry to study the structure of molecules, particularly large biological molecules such as proteins and nucleic acids. It measures the difference in absorption of left-handed and right-handed circularly polarized light by a sample. This difference in absorption can provide information about the three-dimensional structure of the molecule, including its chirality or "handedness."

In more technical terms, CD is a form of spectroscopy that measures the differential absorption of left and right circularly polarized light as a function of wavelength. The CD signal is measured in units of millidegrees (mdeg) and can be positive or negative, depending on the type of chromophore and its orientation within the molecule.

CD spectra can provide valuable information about the secondary and tertiary structure of proteins, as well as the conformation of nucleic acids. For example, alpha-helical proteins typically exhibit a strong positive band near 190 nm and two negative bands at around 208 nm and 222 nm, while beta-sheet proteins show a strong positive band near 195 nm and two negative bands at around 217 nm and 175 nm.

CD spectroscopy is a powerful tool for studying the structural changes that occur in biological molecules under different conditions, such as temperature, pH, or the presence of ligands or other molecules. It can also be used to monitor the folding and unfolding of proteins, as well as the binding of drugs or other small molecules to their targets.

Virus replication is the process by which a virus produces copies or reproduces itself inside a host cell. This involves several steps:

1. Attachment: The virus attaches to a specific receptor on the surface of the host cell.
2. Penetration: The viral genetic material enters the host cell, either by invagination of the cell membrane or endocytosis.
3. Uncoating: The viral genetic material is released from its protective coat (capsid) inside the host cell.
4. Replication: The viral genetic material uses the host cell's machinery to produce new viral components, such as proteins and nucleic acids.
5. Assembly: The newly synthesized viral components are assembled into new virus particles.
6. Release: The newly formed viruses are released from the host cell, often through lysis (breaking) of the cell membrane or by budding off the cell membrane.

The specific mechanisms and details of virus replication can vary depending on the type of virus. Some viruses, such as DNA viruses, use the host cell's DNA polymerase to replicate their genetic material, while others, such as RNA viruses, use their own RNA-dependent RNA polymerase or reverse transcriptase enzymes. Understanding the process of virus replication is important for developing antiviral therapies and vaccines.

A plasmid is a small, circular, double-stranded DNA molecule that is separate from the chromosomal DNA of a bacterium or other organism. Plasmids are typically not essential for the survival of the organism, but they can confer beneficial traits such as antibiotic resistance or the ability to degrade certain types of pollutants.

Plasmids are capable of replicating independently of the chromosomal DNA and can be transferred between bacteria through a process called conjugation. They often contain genes that provide resistance to antibiotics, heavy metals, and other environmental stressors. Plasmids have also been engineered for use in molecular biology as cloning vectors, allowing scientists to replicate and manipulate specific DNA sequences.

Plasmids are important tools in genetic engineering and biotechnology because they can be easily manipulated and transferred between organisms. They have been used to produce vaccines, diagnostic tests, and genetically modified organisms (GMOs) for various applications, including agriculture, medicine, and industry.

An oncogene fusion, also known as oncogenic fusion or chimeric oncogene, is a result of a genetic rearrangement where parts of two different genes combine to form a hybrid gene. This fusion can lead to the production of an abnormal protein that contributes to cancer development and progression. In many cases, one of the fused genes is a proto-oncogene, a normal gene that regulates cell growth and division. When this gene is altered through fusion, it can acquire increased activity or new functions, promoting uncontrolled cell growth and eventually leading to tumor formation. Oncogene fusions are often associated with specific types of cancer and can be used as diagnostic markers or therapeutic targets for cancer treatment.

Glycoproteins are complex proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide backbone. These glycans are linked to the protein through asparagine residues (N-linked) or serine/threonine residues (O-linked). Glycoproteins play crucial roles in various biological processes, including cell recognition, cell-cell interactions, cell adhesion, and signal transduction. They are widely distributed in nature and can be found on the outer surface of cell membranes, in extracellular fluids, and as components of the extracellular matrix. The structure and composition of glycoproteins can vary significantly depending on their function and location within an organism.

Glutathione transferases (GSTs) are a group of enzymes involved in the detoxification of xenobiotics and endogenous compounds. They facilitate the conjugation of these compounds with glutathione, a tripeptide consisting of cysteine, glutamic acid, and glycine, which results in more water-soluble products that can be easily excreted from the body.

GSTs play a crucial role in protecting cells against oxidative stress and chemical injury by neutralizing reactive electrophilic species and peroxides. They are found in various tissues, including the liver, kidneys, lungs, and intestines, and are classified into several families based on their structure and function.

Abnormalities in GST activity have been associated with increased susceptibility to certain diseases, such as cancer, neurological disorders, and respiratory diseases. Therefore, GSTs have become a subject of interest in toxicology, pharmacology, and clinical research.

A Structure-Activity Relationship (SAR) in the context of medicinal chemistry and pharmacology refers to the relationship between the chemical structure of a drug or molecule and its biological activity or effect on a target protein, cell, or organism. SAR studies aim to identify patterns and correlations between structural features of a compound and its ability to interact with a specific biological target, leading to a desired therapeutic response or undesired side effects.

By analyzing the SAR, researchers can optimize the chemical structure of lead compounds to enhance their potency, selectivity, safety, and pharmacokinetic properties, ultimately guiding the design and development of novel drugs with improved efficacy and reduced toxicity.

Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:

1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction

Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:

1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.

Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.

Transfection is a term used in molecular biology that refers to the process of deliberately introducing foreign genetic material (DNA, RNA or artificial gene constructs) into cells. This is typically done using chemical or physical methods, such as lipofection or electroporation. Transfection is widely used in research and medical settings for various purposes, including studying gene function, producing proteins, developing gene therapies, and creating genetically modified organisms. It's important to note that transfection is different from transduction, which is the process of introducing genetic material into cells using viruses as vectors.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

An amino acid substitution is a type of mutation in which one amino acid in a protein is replaced by another. This occurs when there is a change in the DNA sequence that codes for a particular amino acid in a protein. The genetic code is redundant, meaning that most amino acids are encoded by more than one codon (a sequence of three nucleotides). As a result, a single base pair change in the DNA sequence may not necessarily lead to an amino acid substitution. However, if a change does occur, it can have a variety of effects on the protein's structure and function, depending on the nature of the substituted amino acids. Some substitutions may be harmless, while others may alter the protein's activity or stability, leading to disease.

Beta-galactosidase is an enzyme that catalyzes the hydrolysis of beta-galactosides into monosaccharides. It is found in various organisms, including bacteria, yeast, and mammals. In humans, it plays a role in the breakdown and absorption of certain complex carbohydrates, such as lactose, in the small intestine. Deficiency of this enzyme in humans can lead to a disorder called lactose intolerance. In scientific research, beta-galactosidase is often used as a marker for gene expression and protein localization studies.

Temperature, in a medical context, is a measure of the degree of hotness or coldness of a body or environment. It is usually measured using a thermometer and reported in degrees Celsius (°C), degrees Fahrenheit (°F), or kelvin (K). In the human body, normal core temperature ranges from about 36.5-37.5°C (97.7-99.5°F) when measured rectally, and can vary slightly depending on factors such as time of day, physical activity, and menstrual cycle. Elevated body temperature is a common sign of infection or inflammation, while abnormally low body temperature can indicate hypothermia or other medical conditions.

A chick embryo refers to the developing organism that arises from a fertilized chicken egg. It is often used as a model system in biological research, particularly during the stages of development when many of its organs and systems are forming and can be easily observed and manipulated. The study of chick embryos has contributed significantly to our understanding of various aspects of developmental biology, including gastrulation, neurulation, organogenesis, and pattern formation. Researchers may use various techniques to observe and manipulate the chick embryo, such as surgical alterations, cell labeling, and exposure to drugs or other agents.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

A genetic vector is a vehicle, often a plasmid or a virus, that is used to introduce foreign DNA into a host cell as part of genetic engineering or gene therapy techniques. The vector contains the desired gene or genes, along with regulatory elements such as promoters and enhancers, which are needed for the expression of the gene in the target cells.

The choice of vector depends on several factors, including the size of the DNA to be inserted, the type of cell to be targeted, and the efficiency of uptake and expression required. Commonly used vectors include plasmids, adenoviruses, retroviruses, and lentiviruses.

Plasmids are small circular DNA molecules that can replicate independently in bacteria. They are often used as cloning vectors to amplify and manipulate DNA fragments. Adenoviruses are double-stranded DNA viruses that infect a wide range of host cells, including human cells. They are commonly used as gene therapy vectors because they can efficiently transfer genes into both dividing and non-dividing cells.

Retroviruses and lentiviruses are RNA viruses that integrate their genetic material into the host cell's genome. This allows for stable expression of the transgene over time. Lentiviruses, a subclass of retroviruses, have the advantage of being able to infect non-dividing cells, making them useful for gene therapy applications in post-mitotic tissues such as neurons and muscle cells.

Overall, genetic vectors play a crucial role in modern molecular biology and medicine, enabling researchers to study gene function, develop new therapies, and modify organisms for various purposes.

Transcription factors are proteins that play a crucial role in regulating gene expression by controlling the transcription of DNA to messenger RNA (mRNA). They function by binding to specific DNA sequences, known as response elements, located in the promoter region or enhancer regions of target genes. This binding can either activate or repress the initiation of transcription, depending on the properties and interactions of the particular transcription factor. Transcription factors often act as part of a complex network of regulatory proteins that determine the precise spatiotemporal patterns of gene expression during development, differentiation, and homeostasis in an organism.

DNA primers are short single-stranded DNA molecules that serve as a starting point for DNA synthesis. They are typically used in laboratory techniques such as the polymerase chain reaction (PCR) and DNA sequencing. The primer binds to a complementary sequence on the DNA template through base pairing, providing a free 3'-hydroxyl group for the DNA polymerase enzyme to add nucleotides and synthesize a new strand of DNA. This allows for specific and targeted amplification or analysis of a particular region of interest within a larger DNA molecule.

Translocation, genetic, refers to a type of chromosomal abnormality in which a segment of a chromosome is transferred from one chromosome to another, resulting in an altered genome. This can occur between two non-homologous chromosomes (non-reciprocal translocation) or between two homologous chromosomes (reciprocal translocation). Genetic translocations can lead to various clinical consequences, depending on the genes involved and the location of the translocation. Some translocations may result in no apparent effects, while others can cause developmental abnormalities, cancer, or other genetic disorders. In some cases, translocations can also increase the risk of having offspring with genetic conditions.

Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).

Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.

Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.

DNA-binding proteins are a type of protein that have the ability to bind to DNA (deoxyribonucleic acid), the genetic material of organisms. These proteins play crucial roles in various biological processes, such as regulation of gene expression, DNA replication, repair and recombination.

The binding of DNA-binding proteins to specific DNA sequences is mediated by non-covalent interactions, including electrostatic, hydrogen bonding, and van der Waals forces. The specificity of binding is determined by the recognition of particular nucleotide sequences or structural features of the DNA molecule.

DNA-binding proteins can be classified into several categories based on their structure and function, such as transcription factors, histones, and restriction enzymes. Transcription factors are a major class of DNA-binding proteins that regulate gene expression by binding to specific DNA sequences in the promoter region of genes and recruiting other proteins to modulate transcription. Histones are DNA-binding proteins that package DNA into nucleosomes, the basic unit of chromatin structure. Restriction enzymes are DNA-binding proteins that recognize and cleave specific DNA sequences, and are widely used in molecular biology research and biotechnology applications.

Immunoglobulin Fc fragments are the crystallizable fragment of an antibody that is responsible for effector functions such as engagement with Fc receptors on immune cells, activation of the complement system, and neutralization of toxins. The Fc region is located at the tail end of the Y-shaped immunoglobulin molecule, and it is made up of constant regions of the heavy chains of the antibody.

When an antibody binds to its target antigen, the Fc region can interact with other proteins in the immune system, leading to a variety of responses such as phagocytosis, antibody-dependent cellular cytotoxicity (ADCC), and complement activation. These effector functions help to eliminate pathogens and infected cells from the body.

Immunoglobulin Fc fragments can be produced artificially through enzymatic digestion of intact antibodies, resulting in a fragment that retains the ability to interact with Fc receptors and other proteins involved in immune responses. These fragments have potential therapeutic applications in a variety of diseases, including autoimmune disorders, inflammatory conditions, and cancer.

Fusogens involved in virus-to-cell fusion mechanisms were the first of these proteins to be discovered. Viral fusion proteins ... Cell fusion also occurs in a multitude of mammalian cells including gametes and myoblasts. Proteins that allow viral or cell ... It also must construct necessary proteins to mediate fusion. Finally, it must eliminate hindrances to fusion. For example, a ... A fusion mechanism is any mechanism by which cell fusion or virus-cell fusion takes place, as well as the machinery that ...
It is a domesticated instance of a viral class II fusion protein. Fédry J, Liu Y, Péhau-Arnaudet G, Pei J, Li W, Tortorici MA, ... HAP2 (hapless 2), also known as GCS1 (generative cell-specific protein 1), is a family of membrane fusion proteins found in the ... February 2017). "The Ancient Gamete Fusogen HAP2 Is a Eukaryotic Class II Fusion Protein". Cell. 168 (5): 904-915.e10. doi: ... This protein is essential for gamete fusion, and therefore fertilization, in these organisms. ...
HIV infects Helper CD4+ T cells and makes them produce viral proteins, including fusion proteins. Then, the cells begin to ... the fusion protein allows it to bind with the host cell. The HN and fusion proteins are then left on the host cell walls, ... During infection, viral fusion proteins used by the virus to enter the cell are transported to the cell surface, where they can ... Typically, the viral families that can cause syncytia are enveloped, because viral envelope proteins on the surface of the host ...
The fusion of the cells is apparently caused by viral fusion proteins from endosymbiotic endogenous retrovirus. An ... immunoevasive action was the initial normal behavior of the viral protein, in order to avail for the virus to spread to other ... Feb 2000). "Syncytin is a captive retroviral envelope protein involved in human placental morphogenesis". Nature. 403 (6771): ... also known as placental protein 14). Regulatory T cells also likely play a role. Also, a shift from cell-mediated immunity ...
F-protein, as other paramyxoviral fusion proteins, is a trimeric class I viral membrane fusion protein. It is produced in the ... matrix protein (M), fusion protein (F), neuraminidase (NA) and large protein (L). All these proteins have variable functions ... as other Paramyxovirus structural fusion proteins is a trimeric molecule that belongs to class I viral membrane fusion proteins ... sites of the respiratory syncytial virus fusion protein in Sendai virus fusion protein leads to enhanced cell-cell fusion and a ...
The E1 gene is a membrane fusion protein that is important in viral entry and release. Together, E1 and E2 are the ... Cholesterol is also necessary for the Alphavirus to undergo fusion. This fusion of the endosomal membrane to the viral envelope ... The sgRNA codes for the structural proteins that will form the new virus. The assembly of the new viral capsid occurs in the ... After being taken in through endocytosis, a low pH triggers a membrane fusion, which delivers the viral RNA genomes into the ...
This protein is a fusion product of a viral nucleocapsid protein and a bacterial MBP protein. A phase III clinical trial to ... namely a gene encoding a viral nucleocapsid protein and a gene encoding a bacterial maltose-binding protein (MBP). The fusion ... In all of these patents, the carrier protein is referred to as a chimeric fusion protein with an amino acid sequence derived ... viral nucleocapsid protein and bacterial maltose-binding protein). In addition, the polyhistidine-tag - a short peptide that is ...
She showed that the transmembrane domain of viral fusion proteins can be conformationally plastic, and the β-sheet conformation ... Yao, Hongwei; Lee, Michelle W.; Waring, Alan J.; Wong, Gerard C. L.; Hong, Mei (2015-08-17). "Viral fusion protein ... and viral fusion proteins. She determined the structure of the membrane toroidal pores formed by the antimicrobial peptide ... In 2020 she determined both the influenza B M2 protein structure and the SARS-CoV-2 envelope protein structure, the latter in ...
The H protein mediates receptor attachment and the F protein causes fusion of viral envelope and cellular membrane. ... The RNA genome of the virus codes 6 main proteins Nucleoprotein (N), Phosphoprotein (P), Matrix protein (M), Fusion protein (F ... The measles virus has two envelope glycoproteins on the viral surface - hemagglutinin (H) and membrane fusion protein (F). ... producing all viral proteins. The viruses are then assembled from their proteins and negative sense ssRNA, and the cell will ...
... computational analyses suggest that the carboxyl terminal glycoproteins of Bunyaviruses are class II viral fusion protein (beta ... Viral proteins begin undergoing translation before the transcription of mRNA has finished. The Gn and Gc phlebovirus proteins ... The small segment (S) codes for the viral N protein and a non structural protein, NSs via an ambisense coding strategy. The ... The configuration of Gn and Gc proteins in the viral envelope imposes the order of the particle. The viral envelope forms an ...
... either of the fusion protein or of a companion protein, is necessary for the majority of viral fusion proteins. The priming ... The membrane fusion event that triggers viral entrance is caused by the viral fusion protein. Many enveloped viruses only have ... A viral envelope protein or E protein is a protein in the envelope, which may be acquired by the capsid from an infected host ... So far, structural studies have revealed two kinds of viral fusion proteins. These proteins are believed to catalyze the same ...
In some cases, expression of viral fusion proteins on the surface of the host cells can cause host cell fusion to form ... A viral infection does not always cause disease. A viral infection simply involves viral replication in the host, but disease ... Viral genetics encoding viral factors will determine the degree of viral pathogenesis. This can be measured as virulence, which ... proteins, DNA and/or RNA. Namely, viral proteins of herpes simplex virus can degrade host DNA and inhibit host cell DNA ...
TMPRSS2 is needed to cleave the spike protein for viral fusion to cell membrane. However, a recent study has demonstrated that ... Furthermore, within the viral genome, there are not only instructions to synthesize viral proteins but also other virulence ... These ligands not only consist of endogenous proteins but also bacterial and viral products. Once the virus is anchored to the ... Ebola is one viral hemorrhagic fever virus that causes Ebola Virus Disease (EVD). Analysis of human samples of nonsurvivors of ...
For example, neutralizing antibodies can prevent conformational changes of viral proteins that mediate the membrane fusion ... thereby improving recognition of viral particles. Conserved parts of viral proteins that play a central role in viral function ... In case of a viral infection, NAbs can bind to glycoproteins of enveloped viruses or capsid proteins of non-enveloped viruses. ... Viruses with a low density of surface structural proteins are more difficult for antibodies to bind to. Some viral ...
Fusion of these membranes allows the viral proteins and genome to be released into the host cell, which then causes the ... hemagglutinin-esterase fusion (HEF). These glycoproteins allow for attachment and fusion of viral and cellular membranes. ... In each of these techniques, the antibodies for the protein of interest are added and the presence of the specific protein is ... Type D has 7 RNA segments and encodes 9 proteins, while Types A and B have 8 RNA segments and encode at least 10 proteins.[ ...
Fusion of these membranes allows the viral proteins and genome to be released into the host cell, which then causes the ... hemagglutinin-esterase fusion (HEF). These glycoproteins allow for attachment and fusion of viral and cellular membranes. ... Type C has 7 RNA segments and encodes 9 proteins, while Types A and B have 8 RNA segments and encode at least 10 proteins.[ ... In each of these techniques, the antibodies for the protein of interest are added and the presence of the specific protein is ...
... there are two classes of viral fusion proteins: acidic and pH-independent. pH independent fusion proteins can function under ... The first of these proteins to be studied were the viral fusion proteins, which allow an enveloped virus to insert its genetic ... White, J M (1990). "Viral and Cellular Membrane Fusion Proteins". Annual Review of Physiology. 52: 675-97. doi:10.1146/annurev. ... Even the entry of pathogens can be governed by fusion, as many bilayer-coated viruses have dedicated fusion proteins to gain ...
The fusion protein (F) is an integral membrane protein, sharing many features similar to other viral fusion proteins and is ... a matrix protein (M), a fusion protein (F), a hemagglutinin-neuraminidase (Hn) protein and a large polymerase protein (L). A ... The structure of the envelope is characterized by the spike-like projections of two viral proteins, the fusion protein (F) and ... The M protein interacts with the Hn and F proteins, helping to incorporate these proteins into viral particles for release. It ...
Interestingly, a 40 kDa X-Core fusion protein is encoded by a long viral 3.9-kb transcript, whose function remains unclear. ... viral DNA polymerase is used for a later stage) and removal of the viral polymerase protein (P) from the (−) sense strand and a ... Viral infection by hepatitis B virus (HBV) causes many hepatocyte changes due to the direct action of a protein encoded by the ... The core proteins dissociate from the partially double stranded viral DNA, which is then made fully double stranded (by host ...
The alphaviral glycoprotein E1 is a class II viral fusion protein, which is structurally different from the class I fusion ... The second encodes three structural proteins: the core nucleocapsid protein C, and the envelope proteins P62 and E1, which ... Most alphaviruses lose the peripheral protein E3, but in Semliki viruses it remains associated with the viral surface. Four ... The first is non-structural and encodes proteins (nsP1-nsP4) necessary for transcription and replication of viral RNA. ...
... also known as the S protein, on their surfaces; S is a class I fusion protein and is responsible for mediating viral entry as ... They may also form protein-protein interactions with other viral proteins, such as those forming the nucleocapsid.: 51-2 They ... 33 Many spike proteins are membrane fusion proteins. Being exposed on the surface of the virion, spike proteins can be antigens ... In virology, a spike protein or peplomer protein is a protein that forms a large structure known as a spike or peplomer ...
Next in the cycle is the fusion of the viral and host membranes which is likely mediated by the F protein. Though the fusion ... "Roles of the Putative Integrin-Binding Motif of the Human Metapneumovirus Fusion (F) Protein in Cell-Cell Fusion, Viral ... This allows infected cells to merge with adjacent cells through the action of viral fusion proteins on the surface, effectively ... After fusion, the viral ribonucleoprotein (RNP) containing negative-sense viral RNA (vRNA) genome is released into the ...
An example of a Class III viral fusion protein is the rabies virus glycoprotein, G. Class IV: Class IV viral fusion proteins ... The fusion of the viral envelope with the cellular membrane requires high energy to occur. Viral membrane fusion proteins act ... and groups of viral proteins include structural proteins, nonstructural proteins, regulatory proteins, and accessory proteins. ... Examples of class II viral fusion proteins include the dengue virus E protein, and the west nile virus E protein. Class III: ...
The viral genome and associated viral proteins is released into the cytoplasm following fusion of the viral envelope and the ... Several of the proteins encoded by the BoDV-1 genome have been characterised. The G glycoprotein is important for viral entry ... It has been suggested that the p10, or X, protein plays a role in viral RNA synthesis or ribonucleoprotein transport. The P40 ... "A short leucine-rich sequence in the Borna disease virus p10 protein mediates association with the viral phospho- and ...
This fusion involves conformational changes of viral fusion proteins and protein docking, but the exact molecular mechanisms ... Folding@home has also been used to study membrane fusion, an essential event for viral infection and a wide range of biological ... Protein folding is driven by the search to find the most energetically favorable conformation of the protein, i.e., its native ... Thus, understanding protein folding is critical to understanding what a protein does and how it works, and is considered a holy ...
... as the critical roles of the membrane regions in immune receptor clustering and activation and in viral membrane fusion protein ... of cell surface proteins, particularly those of immune receptors and viral membrane proteins. James J. Chou was born in ... proteins to fill the knowledge gap in the transmembrane and membrane-proximal regions of several immune receptors and viral ... He then received Ph.D. in Biophysics from the Harvard University, where he studied protein NMR spectroscopy under the ...
All of the viral fusion proteins undergo a remarkable protein refolding event and this process brings about fusion of the viral ... Studies on the fusion protein were applicable to the envelope proteins of SARS coronavirus, HIV and Ebola virus. ... Their work mainly focused on sequencing viral genes and characterizing viral proteins. During this time, Lamb characterized the ... fusion protein. Proceedings of the National Academy of Sciences (2005) Structure of the parainfluenza virus 5 F protein in its ...
Also, viral fusion proteins cause the formation of the placental syncytium to limit exchange of migratory cells between the ... The fusion proteins were a way to spread the infection to other cells by simply merging them with the infected one (HIV does ... Most viral vaccines are based on live attenuated viruses, whereas many bacterial vaccines are based on acellular components of ... One of the pathways is siRNA in which long double stranded RNA is cut into pieces that serve as templates for protein complex ...
... as well as its structural homology to other viral fusion proteins. PDB: 3NW8​; Stampfer SD, Lou H, Cohen GH, Eisenberg RJ, ... Protein pages needing a picture, Viral structural proteins, Herpes, Protein domains, Protein families, Membrane proteins, All ... Other viral glycoproteins involved in the process of viral cell entry include gC, gB, gD, gH, and gL, but only gC, gB, gD, and ... The herpesvirus glycoprotein B is the most highly conserved of all surface glycoproteins and acts primarily as a fusion protein ...
Interbilayer forces in membrane fusion Viral membrane fusion proteins Classification of viral fusion proteins in TCDB database ... Membrane fusion proteins (not to be confused with chimeric or fusion proteins) are proteins that cause fusion of biological ... There are four groups of fusion proteins categorized by their structure and mechanism of fusion. Class I fusion proteins ... These proteins originate from the env gene of endogenous retroviruses. They are domesticated viral class I fusion proteins. ...
Treating Bladder Cancer: Engineering of Current and Next Generation Antibody-, Fusion Protein-, mRNA-, Cell- and Viral-Based ... Treating Bladder Cancer: Engineering of Current and Next Generation Antibody-, Fusion Protein-, mRNA-, Cell- and Viral-Based ... Treating Bladder Cancer: Engineering of Current and Next Generation Antibody-, Fusion Protein-, mRNA-, Cell- and Viral-Based ... Antibody and protein technologies came a long way in recent years and new engineering approaches were applied to generate ...
One of human HCC cell lines, HepG2 cells, was transfected to stably express HBx protein (HBx(+)-H … ... The cross-talk between the hepatitis B virus X protein (HBx) and B7-H1 in hepatocarcinoma (HCC) is unclear. This study analyzed ... Viral Fusion Proteins / genetics * Viral Fusion Proteins / immunology * Viral Fusion Proteins / metabolism* ... The cross-talk between the hepatitis B virus X protein (HBx) and B7-H1 in hepatocarcinoma (HCC) is unclear. This study analyzed ...
... termed the fusion protein, which is a key therapeutic target. Viral fusion proteins have been studied [...] Read more. ... termed the fusion protein, which is a key therapeutic target. Viral fusion proteins have been studied for decades, and numerous ... As the major viral proteins present on the surface of virions, viral envelope proteins are a prominent target of the host ... As the major viral proteins present on the surface of virions, viral envelope proteins are a prominent target of the host ...
For some negative-strand RNA viruses (e.g., vesicular stomatitis virus and Ebola virus), the viral matrix (M) protein contains ... Enveloped viruses are released from infected cells after coalescence of viral components at cellular membranes and budding of ... Coexpression of M protein with the viral hemagglutinin-neuraminidase (HN) or fusion (F) glycoproteins also failed to result in ... For some negative-strand RNA viruses (e.g., vesicular stomatitis virus and Ebola virus), the viral matrix (M) protein contains ...
Fusogens involved in virus-to-cell fusion mechanisms were the first of these proteins to be discovered. Viral fusion proteins ... Cell fusion also occurs in a multitude of mammalian cells including gametes and myoblasts. Proteins that allow viral or cell ... It also must construct necessary proteins to mediate fusion. Finally, it must eliminate hindrances to fusion. For example, a ... A fusion mechanism is any mechanism by which cell fusion or virus-cell fusion takes place, as well as the machinery that ...
... the mechanism of viral fusion proteins; and assembly of the vertebrate heart. He has served on national review panels of both ... The proteins of the coagulation cascade are produced in the liver and secreted into the blood. So, the target tissue for ... F8 and F9 are not large proteins, so the DNA sequence encoding their mRNA can "fit into" the vectors used to deliver them to ... The malaria parasite does not survive well in red blood cells carrying the HbS protein. HbS is most common in equatorial Africa ...
2. Structure and Neutralization of Viral Fusion Proteins Casner, Ryan Gavin 2023 Theses BiochemistryCOVID-19 (Disease) ... CysZ: Structural and Functional Studies of a Novel Sulfate Transport Protein Assur, Zahra 2013 Theses CytologyCarrier proteins ... Bacterial proteinsRibosomesBiochemistryProteins--SynthesisBiophysics 33. RPGRIP1L and FTO - genes implicated in the effects of ... Molecular dynamicsComputer simulationProteinsProtein folding 13. Dual tRNA mimicry in the Cricket Paralysis Virus IRES uncovers ...
... supporting viral dissemination, and thereby establishing widespread and lifelong infection, processes where receptor signaling ... G protein-coupled receptors (GPCRs) constitute a family of receptors with seven transmembrane alpha-helical domains (7TM ... Teissier, E.; Pécheur, E.I. Lipids as modulators of membrane fusion mediated by viral fusion proteins. Eur. Biophys. J. 2007, ... These proteins are involved in DNA replication (e.g., DNA polymerase), viral entry, cell-to-cell spread, immunevasion, and ...
Categories: Viral Fusion Proteins Image Types: Photo, Illustrations, Video, Color, Black&White, PublicDomain, ...
Turns out, that this protein look exactly like a class II viral fusion protein. Now, the question if of course - is it of viral ... The extra sequences at the N-termini of viral jelly roll capsid proteins, involved in recognizing the viral genome, likely ... The viral core protein retains protease activity, needed for cleavage from a protein precursor. ... The matrix Z proteins of arenaviruses are related to cellular RING domain proteins, and the matrix proteins of some negative ...
09185 Viral protein families. 03200 Viral proteins. K19251 HA; Influenza A virus hemagglutinin. 03210 Viral fusion proteins. ... Viral proteins [BR:ko03200]. -ssRNA viruses. Influenza virus. K19251 HA; Influenza A virus hemagglutinin. Viral fusion proteins ... Class I fusion proteins. Orthomyxoviridae. K19251 HA; Influenza A virus hemagglutinin. Virus entry [br03220.html]. Viral entry ... 03230 Viral genome structure. K19251 HA; Influenza A virus hemagglutinin. 03261 Virion - Influenza A virus. K19251 HA; ...
... expert in molecular modeling and viral fusion proteins. These antigens were designed to mimic the structure of the MPER on the ... HIV-1 envelope proteins complete their folding into six-helix bundles immediately after fusion pore formation. Mol Biol Cell ... A total of 8 combinations of E1/E2 peptides and 3 fusion proteins were tested. The interaction of 2F5 and 4E10 MAbs with these ... Targeting therapeutics to an exposed and conserved binding element of the HIV-1 fusion protein. Proc Natl Acad Sci U S A 2003 ...
Class h: Coiled coil proteins [57942] (5 folds). *. Fold h.3: Stalk segment of viral fusion proteins [58063] (3 superfamilies) ... Family h.3.2.1: Virus ectodomain [58070] (6 proteins). *. Protein Stalk of the ectodomain of NDV fusion glycoprotein [69983] (1 ... PDB Description: fragment of fusion protein from newcastle disease virus. SCOP Domain Sequences for d1g5gb2:. Sequence, based ... SCOP: Structural Classification of Proteins and ASTRAL. Release 1.59 (May 2002) Copyright © 1994-2009 The SCOP and Astral ...
Retroviruses rely on low pH to activate their fusion proteins that merge the viral envelope with an endosomal membrane, ... The Avian Leukosis Virus gp95 Fusion Protein (ALV-gp95) Family. 1.G.12 The Avian Leukosis Virus gp95 Fusion Protein (ALV-gp95) ... This family belongs to the: Viral Envelope Fusion Protein (Env-FP) Superfamily. ... View Proteins belonging to: The Avian Leukosis Virus gp95 Fusion Protein (ALV-gp95) Family ...
Infectious pancreatic necrosis virus (IPNV) recombinant viral protein 1 (VP1) and VP2-Flagellin fusion protein elicit distinct ...
Class II viral fusion proteins C-terminal domain [81284] (2 proteins). *. b.1.18.5: Cytomegalovirus protein US2 [81285] (1 ... b.1.18.9: Transglutaminase N-terminal domain [81289] (1 protein). *. b.1.18.10: Filamin repeat (rod domain) [81290] (2 proteins ... b.1.18.17: Copper resistance protein C (CopC, PcoC) [81969] (1 protein). ... b.1.18.13: Cellulosomal scaffoldin protein CipC, module x2.1 [81293] (1 protein). ...
Molecular cloning and viral gene delivery of fusion proteins are powerful tools to elucidate the role and regulation of ... Molecular cloning, viral gene delivery, fusion proteins, central nervous system, PAR2, MeCP2.. ... Minchella, Daniela (2019) Molecular tools for the study of protein levels in the central nervous system: focus on PAR2 and ... Molecular tools for the study of protein levels in the central nervous system: focus on PAR2 and MeCP2 ...
Researchers out of Italy and the United Kingdom found that, contrary to government claims, the spike proteins from shots ... for COVID-19 will make spike proteins in their bodies forever. ... During the penetration process, called "fusion," the viral ... STUDY: Half Of Those Vaccinated For COVID Will Make Spike Proteins FOREVER. by Mac Slavo , Sep 6, 2023 , Headline News , 0 ... A new study has confirmed that half of the people who have been "vaccinated" for COVID-19 will make spike proteins in their ...
... host serine protease TMPRSS2 cleaves the S protein and results in the fusion of the viral and cellular membranes. The S protein ... protein, the membrane (M) protein, and the envelope (E) protein. The receptor-binding domain (RBD) of the S protein of SARS-CoV ... Viral loads and duration of viral shedding in adult patients hospitalized with influenza. J Infect Dis. 2009 Aug 15. 200 (4): ... SARS-CoV-2 encodes four major structural proteins: the spike (S) protein, the nucleocapsid (N) ...
The Coronavirus Spike protein is a class I viral fusion protein and mediates attachment to the host receptor. The size of the ... 6/5/2021 • To start off, it is important to understand how coronavirus enters our cells: spike protein.Spike proteins are ... Armed with the molecular code to the spike protein, the body now knows how to recognize and dismantle it. And with its spike ... The vaccine uses a fragment of the spike protein to get the body to recognize the "flu" and attack it much quicker ………the ...
We propose that additional investigation into the role of ADCP in protective viral responses, the specific virus epitopes ... We propose that additional investigation into the role of ADCP in protective viral responses, the specific virus epitopes ... also provide and interpret evidence from studies that support a potential role for ADCP in either inhibiting or enhancing viral ... also provide and interpret evidence from studies that support a potential role for ADCP in either inhibiting or enhancing viral ...
A single amino acid in the stalk region of the H1N1pdm influenza virus HA protein affects viral fusion, stability and ... Role of viral RNA and lipid in the adverse events associated with the 2010 Southern Hemisphere trivalent influenza vaccine. ... An observational study of febrile seizures: the importance of viral infection and immunization. BMC Pediatr. 2016 Dec 3;16(1): ... Effect of influenza vaccination on viral replication and immune response in persons infected with human immunodeficiency virus ...
... and the key role of a protein grappling hook with which the influenza virus commandeers its prize-your cells. ... Research at Harvard Medical School is shedding new light on the battle line where viral and cell membranes meet, ... "That notion is probably fundamental to all viral fusion proteins-or for that matter to most cellular membrane fusion events ... The study also appears to settle a question about the nature of the hemagglutinin protein, and viral fusion: Are multiple hooks ...
The S protein is a class I viral fusion protein like the influenza virus hemagglutinin (HA); SARS-CoV2 also has an S1/S2 ... matrix protein (M), and small envelope protein (E). The N-protein binds to viral RNA, encloses it in a capsid and assists RNA ... and after RNA replication it guides the viral membrane proteins for viral assembly. The S-protein is essential for attachment ... RNA encodes for 27 viral proteins, of which 16 are non-structural proteins (nsps), and 11 are accessory and structural proteins ...
The anticoagulant nafamostat potently inhibits SARS-CoV-2 S protein-mediated fusion in a cell fusion assay system and viral ... We observed that the S protein of SARS-CoV and SARS-CoV-2 required both hACE2 and TMPRSS2 for fusion activity (Appendix Figure ... We next analyzed the membrane fusion step of Rc-o319 S. A previous study showed that human sarbecovirus S protein was ... that TMPRSS2 activates the severe acute respiratory syndrome coronavirus spike protein for membrane fusion and reduces viral ...
... recombinant proteins, and viral vectors ... Fc-fusions, Fab fragments, ... Protein Biology. Protein application protocols, reagents and resources for your western blotting, ELISA, IHC, flow cytometry, ... From monoclonal antibodies and recombinant proteins to the most advanced cell and gene therapies, our comprehensive set of ... Plasmid and SygRNA® synthetic formats are available to complement our extensive portfolio of Cas9 proteins, plasmids and ...
The flavivirus membrane fusion machinery, like that of many other enveloped viruses, is triggered by the acidic pH in endosomes ... This process is mediated by viral fusion proteins that are associated with the viral membrane and primed to undergo structural ... Although histidines have been speculated to play an important role as acidic pH sensors in class II viral fusion proteins ( ... So far, two structurally unrelated classes of viral fusion proteins have been identified (class I in myxo-, paramyxo-, retro-, ...
Then gp41, the transmembrane protein produces fusion between viral envelope and host membrane. Thus the viral RNA is ... Then gp41, the transmembrane protein produces fusion between viral eavelepe and host membrane. Thus the viral RNA is ... During viral maturation, p-53 is further processed into p-17, p-24, p-7 and p-6 which are then incorporated as core proteins. ... Tat protein also has a stimulatory effect on the growth of Kaposi′s sarcoma cells. The incidence of Kaposi′s sarcoma is 1000 ...
Entry starts with membrane attachment and ends with S protein-catalyzed membrane fusion releasing the viral contents into the ... a key enabler of SARS-CoV-2 infection-to cut the spike protein and facilitate membrane fusion, the team found. The work was led ... Fusion and penetration can occur at the cell surface of cells expressing TMPRSS2 if the extracellular pH is ∼6.8. Credit: ... Fusion and penetration occur only in acidic early and late endosomal/lysosomal compartments but not at the cell surface, even ...
... viral fusion protein) directly from... ... RSV has an RNA genome that encodes 10 viral proteins. The virus ... a lipid envelope that contains viral glycoproteins that are involved in entry of the virus into cells and fusion of the viral ... It is one of the most common viral causes of death in children younger than five years, particularly in children younger than ... It is also the major viral cause of hospital-acquired infection. Children at the greatest risk of severe RSV infections include ...
  • The overall objective of EuroNeut-41 was to design a vaccine that raises antibodies able to prevent HIV cell fusion by blocking the virus fusion protein gp41 in its pre-fusogenic conformation. (europa.eu)
  • We propose that additional investigation into the role of ADCP in protective viral responses, the specific virus epitopes targeted by ADCP antibodies, and the types of phagocytes and Fc receptors involved in ADCP at sites of virus infection will provide insight into strategies to successfully leverage this important immune response for improved antiviral immunity through rational vaccine design. (frontiersin.org)
  • From monoclonal antibodies and recombinant proteins to the most advanced cell and gene therapies, our comprehensive set of products and services will accelerate your workflows, reduce risk, and get you to the finish line faster. (sigmaaldrich.com)
  • We are studying the mechanism of viral membrane fusion and its inhibition by drugs and antibodies. (stanford.edu)
  • Some of our studies are aimed at creating an HIV vaccine that elicits antibodies against a transient, but vulnerable, intermediate in the membrane-fusion process, called the pre-hairpin intermediate. (stanford.edu)
  • Moreover, the fusion glycoproteins are targets of neutralizing antibodies and represent exciting potential candidates for the rational design of new anti-HCMV therapies to prevent or disrupt viral cell entry. (databasefootball.com)
  • NIH research indicates that antibodies specific to the prefusion form had high efficacy preventing viral infection, which indicates that a prefusion F-based vaccine may provide optimal protection against RSV, according to Pfizer. (pharmacytimes.com)
  • and subsequent dissociation of the SU and TM subunits are important in ensuring that critical regions of Env are exposed for the briefest time possible during receptor binding and fusion, when retroviral Env proteins are vulnerable to neutralizing antibodies produced by the host organism. (tufts.edu)
  • Studying viral fusion proteins can allow us to better understand how they shape immune responses and inform the design of therapeutics such as drugs, monoclonal antibodies, and vaccines. (caltech.edu)
  • It discusses the architecture of these viruses and fusion proteins and how small molecules, peptides, and antibodies can target these proteins successfully to treat and prevent disease. (caltech.edu)
  • In contrast, animals that received a sham DNA vaccine (n = 12) had no detectable neutralizing antibodies against IDV, and viral RNA was readily detectable in respiratory tract tissues after intranasal challenge [3 x 10(5) TCID50] with IDV D/OK (n = 6) or D/660 (n = 6). (cdc.gov)
  • Enveloped viruses are released from infected cells after coalescence of viral components at cellular membranes and budding of membranes to release particles. (nih.gov)
  • Proteins that allow viral or cell membranes to overcome barriers to fusion are called fusogens. (wikipedia.org)
  • They form polymeric structures to induce fusion of membranes. (wikipedia.org)
  • Reoviruses do not have membranes themselves, so class IV fusogens are not usually involved in traditional virus-cell fusion. (wikipedia.org)
  • Research at Harvard Medical School is shedding new light on the battle line where viral and cell membranes meet, and the key role of a protein grappling hook with which the influenza virus commandeers its prize-your cells. (harvard.edu)
  • To fuse the two membranes, the virus carries a protein called hemagglutinin (the "H" in H1N1). (harvard.edu)
  • Instead, they observed, the protein remains stretched between the two membranes, like a bridge. (harvard.edu)
  • The study also appears to settle a question about the nature of the hemagglutinin protein, and viral fusion: Are multiple hooks needed because they interact directly with each other to fuse the membranes, or because that's the number required to pull the somewhat elastic membranes together by brute force? (harvard.edu)
  • The virus has a lipid envelope that contains viral glycoproteins that are involved in entry of the virus into cells and fusion of the viral envelope with cell membranes. (quidel.com)
  • The laboratory is also applying single molecule imaging to understand how conformational events in the HIV-1 envelope protein lead to fusion between viral and cellular membranes. (yale.edu)
  • The coronavirus spike (S) glycoprotein is a class I viral fusion protein on the outer envelope of the virion that plays a critical role in viral infection by recognizing host cell receptors and mediating fusion of the viral and cellular membranes. (biolegend.com)
  • The trimeric SARS coronavirus (SARS-CoV-2) S glycoprotein consisting of three S1-S2 heterodimers binds the cellular receptor angiotensin-converting enzyme 2 (ACE2) and mediates fusion of the viral and cellular membranes through a pre- to post-fusion conformation transition. (biolegend.com)
  • Fusion of host and viral membranes is critical for the lifecycle of enveloped viruses. (caltech.edu)
  • The fusion of viral and cell membranes is one of the basic processes in the life cycles of viruses. (bvsalud.org)
  • Their conformational rearrangements lead to the unification of lipid bilayers of cell membranes and viral envelopes and the formation of fusion pores through which the viral genome enters the cytoplasm of the cell. (bvsalud.org)
  • A deep understanding of all the stages of conformational transitions preceding the fusion of viral and cell membranes is necessary for the development of specific inhibitors of viral reproduction. (bvsalud.org)
  • As with all coronaviruses, SARS-CoV-2 cell entry is dependent on its 180-kDa spike (S) protein, which mediates two essential events: binding to ACE2 by the amino-terminal region, and fusion of viral and cellular membranes through the carboxyl-terminal region. (cdc.gov)
  • Using the mutational analysis of recombinant subviral particles of tick-borne encephalitis virus, we provide direct experimental evidence that the initiation of fusion is crucially dependent on the protonation of one of the conserved histidines (His323) at the interface between domains I and III of E, leading to the dissolution of domain interactions and to the exposure of the fusion peptide. (rupress.org)
  • When recombinant SARS-CoV-2 B.1.1.7 Spike Protein S1 is immobilized at 2 μg/mL, recombinant human ACE2-Fc Chimera (Cat. (biolegend.com)
  • Recombinant SARS-CoV-2 B.1.1.7 Spike Protein S1 was aliquoted in PBS at 0.2 mg/mL. (biolegend.com)
  • The 678 amino acid recombinant protein has a predicted molecular mass of approximately 76 kD. (biolegend.com)
  • Viral fusion proteins are necessary for membrane fusion to take place. (wikipedia.org)
  • Class II fusogens have a structure distinct from Class I fusogens, but similarly lower the energy barrier for membrane fusion. (wikipedia.org)
  • However, the method they utilize to induce membrane fusion is mechanistically similar. (wikipedia.org)
  • 2021). Ebola virus glycoprotein interacts with cholesterol to enhance membrane fusion and cell entry. (tcdb.org)
  • That notion is probably fundamental to all viral fusion proteins-or for that matter to most cellular membrane fusion events facilitated by proteins. (harvard.edu)
  • The flavivirus membrane fusion machinery, like that of many other enveloped viruses, is triggered by the acidic pH in endosomes after virus uptake by receptor-mediated endocytosis. (rupress.org)
  • Entry starts with membrane attachment and ends with S protein-catalyzed membrane fusion releasing the viral contents into the cytosol. (phys.org)
  • Exposure of the virus to an acidic milieu is essential for membrane fusion, genome penetration, and productive infection. (phys.org)
  • The acidic environment allows enzymes in the endosome or on the cell surface-including TMPRSS2, a key enabler of SARS-CoV-2 infection-to cut the spike protein and facilitate membrane fusion, the team found. (phys.org)
  • Therefore, we herein established a SARS-CoV-2 spike (S) protein-mediated cell-cell fusion assay and found that SARS-CoV-2 showed a superior plasma membrane fusion capacity compared to that of SARS-CoV. (nature.com)
  • Here we generated a series of lipopeptides derived from EK1 and found that EK1C4 was the most potent fusion inhibitor against SARS-CoV-2 S protein-mediated membrane fusion and pseudovirus infection with IC50s of 1.3 and 15.8 nM, about 241- and 149-fold more potent than the original EK1 peptide, respectively. (nature.com)
  • EK1C4 was also highly effective against membrane fusion and infection of other human coronavirus pseudoviruses tested, including SARS-CoV and MERS-CoV, as well as SARSr-CoVs, and potently inhibited the replication of 5 live human coronaviruses examined, including SARS-CoV-2. (nature.com)
  • Consequently, the mechanism underlying the process of receptor-triggered membrane fusion remains poorly understood for not only HCMV but also for other herpesviruses. (databasefootball.com)
  • Integration of these structures and our knowledge of class III viral fusion proteins has led to a working model of HCMV fusion: gH/gL receptor-binding triggers conformational changes of gB endodomain, which, in turn, triggers two essential steps to actuate virus-cell membrane fusion - exposure of gB fusion loops and unfurling of gB ectodomain. (databasefootball.com)
  • The extra sequences at the N-termini of viral jelly roll capsid proteins, involved in recognizing the viral genome, likely evolved after the capture of these proteins from cells. (virology.ws)
  • RSV has an RNA genome that encodes 10 viral proteins. (quidel.com)
  • For some negative-strand RNA viruses (e.g., vesicular stomatitis virus and Ebola virus), the viral matrix (M) protein contains all of the information needed for budding, since virus-like particles (VLPs) are efficiently released from cells when the M protein is expressed from cDNA. (nih.gov)
  • Virus-cell fusions occur during infections of several viruses that are health concerns relevant today. (wikipedia.org)
  • We have previously discussed the idea that viruses originated from selfish genetic elements such as plasmids and transposons when these nucleic acids acquired structural proteins (see A plasmid on the road to becoming a virus ). (virology.ws)
  • I want to explore in more detail the idea that the structural proteins of viruses likely originated from cell proteins ( link to paper ). (virology.ws)
  • The matrix Z proteins of arenaviruses are related to cellular RING domain proteins, and the matrix proteins of some negative strand RNA viruses are related to cellular cyclophilin. (virology.ws)
  • There are many more examples, providing support for the hypothesis that viruses evolved on multiple instances by recruiting different cell proteins. (virology.ws)
  • Given this information on the origin of viral capsid proteins, we can modify the three hypotheses for the origin of viruses into one. (virology.ws)
  • Now, the question if of course - is it of viral origin or is it a cellular protein co-opted by viruses? (virology.ws)
  • It has been hypothesized that conserved histidines in the class II fusion protein E of these viruses function as molecular switches and, by their protonation, control the fusion process. (rupress.org)
  • The entry of enveloped viruses into host cells involves a fusion step between the viral and a cellular membrane. (rupress.org)
  • a The emerging timeline for highly pathogenic viruses and the proposed Disease X. b Schematic representation of SARS-CoV-2 S protein. (nature.com)
  • For the interested reader, chapter 2 contains a review article that serves as a more in-depth introduction for both viruses as well as how the use of structural biology has informed the study of viral surface proteins and neutralizing antibody responses to them. (caltech.edu)
  • A number of enveloped viruses confer fusion of the viral envelope and the cell membrane using surface viral fusion proteins. (bvsalud.org)
  • It presents a proof-of-concept for the aerosol delivery of fusion inhibitory peptides to protect against measles and other airborne viruses, including SARS-CoV-2, in case of high-risk exposure. (bvsalud.org)
  • Drugs that are designed to block the action of VIRAL FUSION PROTEINS and prevent VIRUSES from entering the cell. (bvsalud.org)
  • We have detected a leucine zipper-like motif in the ectodomain of Sendal virus fusion protein (a. a. 269-307) which is extremely conserved in the family of Sendal viruses. (tau.ac.il)
  • There is evidence that ancestral species of mammals may have incorporated these same proteins into their own cells as a result of infection. (wikipedia.org)
  • This class of fusogens contains some of the proteins utilized by influenza, HIV, coronaviruses, and Ebola during infection. (wikipedia.org)
  • We also provide and interpret evidence from studies that support a potential role for ADCP in either inhibiting or enhancing viral infection. (frontiersin.org)
  • The virus then fuses with the endosome membrane and injects its genetic material (labeled blue) inside the cell-the steps necessary to kick off a cycle of viral infection and replication. (phys.org)
  • The findings, published Sept. 1 in PNAS , provide new insights into the fundamental mechanics of viral infection and could point the way to new methods for intervening before the onset of COVID-19. (phys.org)
  • It is also the major viral cause of hospital-acquired infection. (quidel.com)
  • To develop specific anti-coronavirus therapeutics and prophylactics, the molecular mechanism that underlies viral infection must first be defined. (nature.com)
  • We previously developed a pan-coronavirus fusion inhibitor, EK1, which targeted the HR1 domain and could inhibit infection by divergent human coronaviruses tested, including SARS-CoV and MERS-CoV. (nature.com)
  • A particle according to claim 1 or 2, wherein the heterologous polypeptide has specific binding affinity for a cognate receptor on die surface of an eukaryotic cell, binding to which does not allow infection of the cell by the viral particle. (sumobrain.com)
  • Measles is the most contagious airborne viral infection and the leading cause of child death among vaccine-preventable diseases. (bvsalud.org)
  • We show here that aerosolized lipopeptide fusion inhibitor, derived from heptad-repeat regions of the measles virus (MeV) fusion protein, blocks respiratory MeV infection in a non-human primate model, the cynomolgus macaque. (bvsalud.org)
  • A DNA vaccine expressing consensus hemagglutinin-esterase fusion protein protected guinea pigs from infection by two lineages of influenza D virus. (cdc.gov)
  • Morbidity may result directly from viral infection or may be indirect, due to exacerbation of underlying cardiopulmonary conditions or bacterial superinfection of the lung, paranasal sinuses, or middle ear. (msdmanuals.com)
  • Identification of the viral pathogen would prevent additional evaluation for or treatment of a bacterial infection. (msdmanuals.com)
  • genic models are inadequate for number of activated CD8-positive T LMP1 was strongly expressed in the understanding the cancer etiology in cells increased considerably in the lymphoma tissues but was hardly the context of natural viral infection. (who.int)
  • An analysis of the sequence an structure of major virion proteins has identified likely ancestors in cellular proteins. (virology.ws)
  • Unfortunately, progress has been hindered by a shortage of structural information of these proteins, particularly in their native environment of an infectious virion. (databasefootball.com)
  • These hydrophobic regions are known as fusion peptides or fusion loops, and they are responsible for causing localized membrane instability and fusion. (wikipedia.org)
  • When activated, all of these fusogens form elongated trimeric structures and bury their fusion peptides into the membrane of the target cell. (wikipedia.org)
  • 2014). The three lives of viral fusion peptides. (tcdb.org)
  • AoproS8 showed optimal activity at pH 9.0 and 40 °C. It was used for the production of xanthine oxidase (XOD)-inhibitory peptides from eight food processing protein by-products. (bvsalud.org)
  • A very common motif among viral capsid proteins is called the single jelly roll , made up of eight beta strands in two four-stranded sheets. (virology.ws)
  • Coexpression of M protein with the viral hemagglutinin-neuraminidase (HN) or fusion (F) glycoproteins also failed to result in significant VLP release. (nih.gov)
  • It was found that M protein in the form of VLPs was only secreted from cells, with an efficiency comparable to authentic virus budding, when M protein was coexpressed with one of the two glycoproteins, HN or F, together with the nucleocapsid (NP) protein. (nih.gov)
  • Among the tens of glycoproteins, three - glycoprotein B (gB), which functions as a fusion protein, and glycoprotein H/glycoprotein L (gH/gL) complex, which functions as a receptor-binding protein - are conserved across all herpesviruses, forming the core viral fusion machinery. (databasefootball.com)
  • CsCl density gradient centrifugation indicated that almost all of the NP protein in the cells had assembled into nucleocapsid-like structures. (nih.gov)
  • Retroviral structural proteins also appear to have originated from cell proteins, with clear homologies with matrix, capsid, and nucleocapsid proteins. (virology.ws)
  • A particle according to any one of the preceding claims, wherein the heterologous polypeptide sterically hinders binding of d e viral glycoprotein to its cognate receptor on the eukaryotic cell. (sumobrain.com)
  • A particle according to claim 7 or 8, wherein the heterologous polypeptide undergoes oligomerisation with die same stoichiometry as that with which the fused viral glycoprotein oligomerises. (sumobrain.com)
  • A particle according to claim 11 or 12, wherein the protease cleavage site becomes accessible after the viral glycoprotein has bound to its cognate receptor on the eukaryotic cell. (sumobrain.com)
  • The S glycoprotein is synthesized as a precursor protein consisting of ~1,300 amino acids that is then cleaved into an amino (N)-terminal S1 subunit (~700 amino acids) and a carboxyl (C)-terminal S2 subunit (~600 amino acids). (biolegend.com)
  • Probing Structural Variation and Dynamics in the HIV-1 Env Fusion Glycoprotein. (washington.edu)
  • During entry of alphaviruses, the E1 glycoprotein molecules probably form two separate populations that generate either a fusion pore or ion-permeable pores. (ox.ac.uk)
  • For the rapid qualitative detection of respiratory syncytial virus (RSV) antigen (viral fusion protein), directly from nasopharyngeal swab, nasopharyngeal aspirate or nasal/nasopharyngeal wash specimens. (thomassci.com)
  • Furthermore, mRNA-based pharmaceuticals recently reached the market and CAR-T cells and viral-based gene therapy remain a major focus of biomedical research. (tu-darmstadt.de)
  • Assuming a person got the mRNA variety, the official narrative from the rulers has been that the spike proteins are harmless and only remain for a few days in the arm. (shtfplan.com)
  • The mRNA COVID vaccines contain genetic code to produce the so-called "spike protein," a component of the SARS-CoV-2 virus that allows the virus to penetrate and infect human cells. (shtfplan.com)
  • The Arc gene, which contains remnants of a structural GAG retrotransposon sequence, produces a protein that self-assembles into capsid-like structures harboring Arc mRNA. (lu.se)
  • We report viral sequences from 188 patients across the hospitals and associated clinics in Oregon dating back to the early days of the outbreak. (cdc.gov)
  • To investigate the requirements for budding of the paramyxovirus simian virus 5 (SV5), its M protein was expressed in mammalian cells, and it was found that SV5 M protein alone could not induce vesicle budding and was not secreted from cells. (nih.gov)
  • Viral infections commonly affect the upper or lower respiratory tract. (msdmanuals.com)
  • Viral respiratory infections are typically diagnosed clinically based on symptoms and local epidemiology. (msdmanuals.com)
  • Cell fusion also occurs in a multitude of mammalian cells including gametes and myoblasts. (wikipedia.org)
  • This class of fusogens also includes syncytins, which are utilized in mammalian cell fusions. (wikipedia.org)
  • One example is syncytin , a retroviral protein used for the construction of the mammalian placenta. (virology.ws)
  • Missing from these hypothesis is how nucleic acids became virus particles - that is, how they acquired structural proteins. (virology.ws)
  • It seems likely that viral structural proteins originated from cellular genes. (virology.ws)
  • The core proteins of alphaviruses (think Semliki Forest virus) has structural similarity with chymotrypsin-like serine proteases. (virology.ws)
  • At some point these genetic elements acquired structural proteins from the cells and became bona fide virus particles. (virology.ws)
  • SCOP: Structural Classification of Proteins and ASTRAL. (berkeley.edu)
  • The unusually large size of HCMV, its pleomorphic envelope, the irregularly organized proteins, and the metastable nature of the gB all pose significant technical challenges to high-resolution structural characterization. (databasefootball.com)
  • The first section of this review describes types of viral fusion proteins and is followed by a comparison of the structural features of class I fusion proteins, namely influenza virus hemagglutinin and the S-protein of the human coronavirus. (bvsalud.org)
  • Traditionally, laboratories used viral culture to detect influenza virus and improvements in virus culture techniques allowed for results within 48-72 hours. (quidel.com)
  • Influenza Virus-Liposome Fusion Studies Using Fluorescence Dequenching and Cryo-electron Tomography. (washington.edu)
  • Both methods yield antibody in solution that is free of most other soluble proteins, lipids, etc. (bdbiosciences.com)
  • Conversely, truncation of the F protein cytoplasmic tail was not inhibitory and did not affect the ability of coexpressed wt HN protein to direct the budding of particles. (nih.gov)
  • Many cell proteins have jelly role motifs, and some form 60-subunit virus-like particles in cells. (virology.ws)
  • In addition, 38 constructs were also created through a collaboration with Harvard university, aiming at mimicking the structure of the MPER on the surface of the viral particles. (europa.eu)
  • Viral particles (red) walking across cellular bridges (blue). (yale.edu)
  • In this study, we designed a DNA vaccine expressing consensus hemagglutinin-esterase fusion (HEF) protein (FluD-Vax) and tested its protective efficacy against two lineages of IDV (D/OK and D/660) in guinea pigs. (cdc.gov)
  • A major current interest of the laboratory is to monitor viral spread and aspects of retroviral pathogenesis directly in living animals using multi-photon laser scanning microscopy. (yale.edu)
  • Abstract: Among the five retroviral genera with Class I viral fusion proteins (lentiviruses and the alpha-, beta-, gamma-, and deltaretroviruses) are found either of two mechanisms of Env subunit association - covalent association mediated by disulfide bonding between cysteines, or noncovalent interactions among various residues at the SU/TM interface. (tufts.edu)
  • Molecular cloning and viral gene delivery of fusion proteins are powerful tools to elucidate the role and regulation of proteins within the central nervous system. (gla.ac.uk)
  • Using a microscope developed by first author Tijana Ivanovic, a research fellow in the HMS Department of Biological Chemistry and Molecular Pharmacology , the team looked closely at changes in the protein throughout its assault on the endosome. (harvard.edu)
  • RSV has two molecular subtypes A and B and RSVpreF is bivalent vaccine based on the crystal structure of pre-fusion F and which is a vital form of the viral fusion protein (F) that RSV uses to attack human cells. (hospitalhealthcare.com)
  • EirGenix is the leading company in biologics development and GMP manufacturing and has solid experience in various biologics (mAb, bi-specific mAbs, r-proteins, COVID-19 Spike protein, fusion proteins, RNA, ADC, Viral Vector, etc. (bio.org)
  • Transmembrane envelope protein of the HUMAN IMMUNODEFICIENCY VIRUS which is encoded by the HIV env gene. (musc.edu)
  • Attachment inhibitors bind to a specific protein on the outer surface of HIV. (medlineplus.gov)
  • The fusion protein is activated in the endosome and for steric reasons only a fraction of the activated molecules can interact with the endosomal membrane. (ox.ac.uk)
  • A fusion mechanism is any mechanism by which cell fusion or virus-cell fusion takes place, as well as the machinery that facilitates these processes. (wikipedia.org)
  • RSV is a major viral pathogen causing severe lung disease in the adult population, particularly among the elderly and which constitutes a substantial disease burden. (hospitalhealthcare.com)
  • A new study has confirmed that half of the people who have been "vaccinated" for COVID-19 will make spike proteins in their bodies forever. (shtfplan.com)
  • Researchers out of Italy and the United Kingdom found that, contrary to government claims, the spike proteins from shots persist in recipients' arms for at least six months post-injection. (shtfplan.com)
  • The first part of the video shown here follows a virus engineered to sprout SARS-CoV-2 spike proteins (labeled pink) as it is captured at a cell surface and engulfed by a cellular compartment called an endosome. (phys.org)
  • Fifty-one vaccine candidates were designed mainly to mimic fusion intermediate conformations of gp41 and in some instance to increase exposure of the 2F5/4E10 epitopes. (europa.eu)
  • After observing the three groups, it was found that only the people in the vaccinated subgroup were carrying the vaccine-derived spike protein . (shtfplan.com)
  • Similarly, human cells with COVID vaccine genetic code reverse-transcribed into them may also endlessly produce the spike protein for the affected individuals' lives," Chudov says. (shtfplan.com)
  • The vaccine itself contains two preF proteins which protect against the two main form of RSV, A and B which actually have multiple genotypes within each of them . (hospitalhealthcare.com)
  • The insights reported not only provide the structure-function relationship of these fusion proteins, but also highlight the potential for these proteins to advance the development of hMPV vaccines and therapeutics. (lightsources.org)
  • 2011). Imaging single retrovirus entry through alternative receptor isoforms and intermediates of virus-endosome fusion. (tcdb.org)
  • The present study focused on two such proteins, the transmembrane receptor PAR2 and the nuclear epigenetic regulator MeCP2. (gla.ac.uk)
  • The sarbecovirus' spike protein specifically recognizes angiotensin-converting enzyme 2 of R. cornutus , but not humans, as an entry receptor. (cdc.gov)
  • One of human HCC cell lines, HepG2 cells, was transfected to stably express HBx protein (HBx(+)-HepG2). (nih.gov)
  • Flow cytometry and western-blot further demonstrated that B7-H1 protein synthesis was enhanced in HBx(+)-HepG2 cells. (nih.gov)
  • Cell fusion is the formation of a hybrid cell from two separate cells. (wikipedia.org)
  • There are three major actions taken in both virus-cell fusion and cell-cell fusion: the dehydration of polar head groups, the promotion of a hemifusion stalk, and the opening and expansion of pores between fusing cells. (wikipedia.org)
  • However, when they are expressed on the surface of cells, they can induce cell-cell fusion. (wikipedia.org)
  • We know that viral proteins can be returned to cells, where they serve useful functions. (virology.ws)
  • Fusion and penetration can occur at the cell surface of cells expressing TMPRSS2 if the extracellular pH is ∼6.8. (phys.org)
  • d Images of SARS-CoV and SARS-CoV-2 S-mediated cell-cell fusion on 293T/ACE2 cells at 2 h (left) and 24 h (right). (nature.com)
  • SARS-CoV-2 B.1.1.7 Spike Protein S1, amino acid Val16-Arg685 (Accession # QHD43416.1), with (HV69-70del, Y144del, N501Y, A570D, P681H) and a C-terminal 8-His tag was expressed in CHO cells. (biolegend.com)
  • According to Pfizer, RSVpreF is based on foundational basic science discoveries, such as findings from the National Institutes of Health (NIH), detailing the crystal structure of prefusion F, a vital form of the viral fusion protein (F) used by RSV to attack human cells. (pharmacytimes.com)
  • When inducing long-term potentiation (LTP) in the hippocampus, we observed an increase of Arc protein highly correlated with an increase in fluorescent intensity and the number of mCherry-positive cells. (lu.se)
  • The viral core protein retains protease activity, needed for cleavage from a protein precursor. (virology.ws)
  • Then, a high protease activity of 11,023.2 U/mL with a protein concentration of 10.8 mg/mL was obtained through fed-batch fermentation in a 5 L fermenter. (bvsalud.org)
  • The lack of covalent bonding in the Env proteins of these two genera correlates with the lack of a particular cysteine in the TM ectodomain, as well as a couple of other TM sequence features that allow easy distinction between the two TM types--lack of an immunosuppressive domain (ISD) and a longer membrane proximal external region (MPER). (tufts.edu)
  • Antibody and protein technologies came a long way in recent years and new engineering approaches were applied to generate innovative therapeutic entities with novel mechanisms of action. (tu-darmstadt.de)
  • The N-terminal part of gp41 is thought to be involved in CELL FUSION with the CD4 ANTIGENS of T4 LYMPHOCYTES, leading to syncytial formation. (musc.edu)
  • The cross-talk between the hepatitis B virus X protein (HBx) and B7-H1 in hepatocarcinoma (HCC) is unclear. (nih.gov)
  • Fusogens involved in virus-to-cell fusion mechanisms were the first of these proteins to be discovered. (wikipedia.org)
  • Scientists have found the following four classes of fusogens to be involved with virus-cell or cell-cell fusions. (wikipedia.org)
  • Class III fusogens are involved with virus-cell fusions. (wikipedia.org)
  • Once free, the viral RNA is copied, and the hijacked cell begins to manufacture copies of the virus. (harvard.edu)
  • Fármacos diseñados para bloquear la acción de las PROTEÍNAS VIRALES DE FUSIÓN y evitan la entrada de los VIRUS en la célula. (bvsalud.org)
  • Studies using the alphavirus Semliki Forest virus have indicated that the viral E1 fusion protein forms two types of pore: fusion pores and ion-permeable pores. (ox.ac.uk)
  • The heptad repeat 2 domain is a major determinant for enhanced human immunodeficiency virus type 1 (HIV-1) fusion and pathogenicity of a highly pathogenic HIV-1 Env. (musc.edu)
  • Fusion-induced apoptosis contributes to thymocyte depletion by a pathogenic human immunodeficiency virus type 1 envelope in the human thymus. (musc.edu)
  • Susceptibility of goldsinny wrasse, Ctenolabrus rupestris L. (Labridae), to viral haemorrhagic septicaemia virus (VHSV) genotype III: experimental challenge and pathology. (gov.scot)
  • Dual mutation events in the haemagglutinin-esterase and F protein from an Infectious salmon anaemia virus HPR0 genotype promote viral fusion and activation by an ubiquitous host protease. (gov.scot)
  • The data suggest a possible rote of this putative leucine zipper motif in the assembly of the Sendal virus fusion protein in solution and membrane. (tau.ac.il)
  • To enable the tracking of Arc molecules from individual neurons in vivo, we devised an adeno-associated virus (AAV) mediated approach to tag the N-terminal of the mouse Arc protein with a fluorescent reporter using CRISPR/Cas9 homologous. (lu.se)
  • To enable the tracking of Arc molecules from individual neurons in vivo, we devised an adeno-associated virus (AAV) mediated approach to tag the N-terminal of the mouse Arc protein with a fluorescent reporter using CRISPR/Cas9 homologous independent targeted integration (HITI). (lu.se)
  • We solved the X-ray crystal structure of six-helical bundle (6-HB) core of the HR1 and HR2 domains in the SARS-CoV-2 S protein S2 subunit, revealing that several mutated amino acid residues in the HR1 domain may be associated with enhanced interactions with the HR2 domain. (nature.com)
  • We undertook to determine the nature of the subunit association in betaretroviral Env proteins and discovered that they share with lentiviruses an Env structure with noncovalently associated subunits. (tufts.edu)
  • By proximity ligation assay (PLA), we demonstrated that the mCherry-Arc fusion protein retains the Arc function by interacting with the transmembrane protein stargazin in postsynaptic spines. (lu.se)
  • article{3ef64d42-e741-442e-a1b5-bd0843c8bfaa, abstract = {{The activity-regulated cytoskeleton-associated (Arc) protein is essential for synaptic plasticity and memory formation. (lu.se)
  • The formation of ion-permeable pores has not been generally accepted, partly because it was not evident how the protein might form these different pores. (ox.ac.uk)
  • Here it is proposed that the choice of the target membrane determines whether a fusion pore or ion-permeable pores are formed. (ox.ac.uk)
  • It is proposed that the rest of the activated molecules interact with the membrane in which the protein is anchored and that this self-membrane reaction leads to formation of ion-permeable pores, which can be detected in the target membrane after fusion of the viral membrane into the target membrane. (ox.ac.uk)
  • For this reason, similar mechanisms and machinery are utilized in cell-cell fusion. (wikipedia.org)
  • During cell fusion the monomers of these proteins will dissociate but will return to a different trimeric structure after the fusion is complete. (wikipedia.org)
  • These reoviral cell-cell fusogens contain fusion loops that can induce cell fusion. (wikipedia.org)
  • Consequently, the viral membrane and the target cell membrane are also pulled close together. (wikipedia.org)
  • There is also the phenomenon of HAP2 - a fusion protein that is used by many different eucaryotic organisms "all over" the phylogenetic tree (from Chlamydomonas to Bees) for mediating cell-cell fusion, predominantley of gametes. (virology.ws)
  • Secondly, at the onset of the fusion process, these complexes get transferred into the target cell membrane and adopt specific conformations therein. (tcdb.org)
  • During the penetration process, called "fusion," the viral spike protein changes shape, becoming a spear of sorts, penetrating the cell surface. (shtfplan.com)
  • Fusion activity depends on two proteolytic cleavage steps, namely, one typically carried out by furin in the producing cell and the second by TMPRSS2 on the cell surface on in endosomes of the target cell. (phys.org)
  • Fusion and penetration occur only in acidic early and late endosomal/lysosomal compartments but not at the cell surface, even when the furin and TMPRSS2 cleavages have both occurred. (phys.org)
  • Fig. 1: Establishment of SARS-CoV-2 S protein-mediated cell-cell fusion system. (nature.com)
  • A particle according to any one of the preceding claims, wherein heterologous polypeptide sterically hinders fusion of an enveloped viral particle with an eukaryotic cell to which it is bound. (sumobrain.com)
  • A particle according to any one of the preceding claims, wherein the protease cleavage site is accessible to the relevant protease (i.e. that which recognises the cleavage site) before the viral particle becomes bound to an eukaryotic cell. (sumobrain.com)
  • A particle according to any one of claims 1 to 9, wherein the protease cleavage site becomes accessible to die relevant protease only after the viral particle has become bound to an eukaryotic cell. (sumobrain.com)
  • In addition, treatment with an ERS inhibitor markedly suppressed FSK-treated cell fusion in a manner related to downregulation of HtrA4 expression. (bvsalud.org)
  • Inoculation with a high dose strains of LMP1 transgenic mice vide a powerful tool in mechanistic of EBV caused a B-cell lymphopro- were established that express LMP1 studies on the role of individual viral liferative disorder in these mice, under the control of the immunoglob- genes in cancer. (who.int)
  • We use the HIV envelope protein (gp120/gp41) as a model system. (stanford.edu)
  • HIV Envelope Protein gp41" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (musc.edu)
  • This graph shows the total number of publications written about "HIV Envelope Protein gp41" by people in this website by year, and whether "HIV Envelope Protein gp41" was a major or minor topic of these publications. (musc.edu)
  • Below are the most recent publications written about "HIV Envelope Protein gp41" by people in Profiles. (musc.edu)
  • Reducing viral risks through nents and products originated from several expansion of donor history screening, im- hundred donors, she did not contract any provements in testing for infectious disease transfusion-transmitted disease. (who.int)
  • Thymic pathogenicity of an HIV-1 envelope is associated with increased CXCR4 binding efficiency and V5-gp41-dependent activity, but not V1/V2-associated CD4 binding efficiency and viral entry. (musc.edu)
  • In a recent study published in Nature Communications , a team of researchers carrying out experiments at the U.S. Department of Energy's Advanced Photon Source (APS) have isolated and characterized highly stable hMPV fusion (f) proteins that are critical for viral entry. (lightsources.org)
  • Thus, our work provides a useful way for efficient expression of proteases in A. niger and high-value utilization of protein by-products. (bvsalud.org)