Bacterial Outer Membrane Proteins: Proteins isolated from the outer membrane of Gram-negative bacteria.Porins: Porins are protein molecules that were originally found in the outer membrane of GRAM-NEGATIVE BACTERIA and that form multi-meric channels for the passive DIFFUSION of WATER; IONS; or other small molecules. Porins are present in bacterial CELL WALLS, as well as in plant, fungal, mammalian and other vertebrate CELL MEMBRANES and MITOCHONDRIAL MEMBRANES.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Escherichia coli: 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.Membrane Proteins: 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.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Bacterial Proteins: Proteins found in any species of bacterium.Gram-Negative Bacteria: Bacteria which lose crystal violet stain but are stained pink when treated by Gram's method.Periplasm: The space between the inner and outer membranes of a cell that is shared with the cell wall.Molecular Sequence Data: 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.Amino Acid Sequence: 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.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.Lipopolysaccharides: Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Protein Structure, Secondary: 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.Cell Membrane Permeability: A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Adhesins, Bacterial: Cell-surface components or appendages of bacteria that facilitate adhesion (BACTERIAL ADHESION) to other cells or to inanimate surfaces. Most fimbriae (FIMBRIAE, BACTERIAL) of gram-negative bacteria function as adhesins, but in many cases it is a minor subunit protein at the tip of the fimbriae that is the actual adhesin. In gram-positive bacteria, a protein or polysaccharide surface layer serves as the specific adhesin. What is sometimes called polymeric adhesin (BIOFILMS) is distinct from protein adhesin.Intracellular Membranes: Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.Protein Transport: The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.Lipid Bilayers: Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.Polymyxin B: A mixture of polymyxins B1 and B2, obtained from Bacillus polymyxa strains. They are basic polypeptides of about eight amino acids and have cationic detergent action on cell membranes. Polymyxin B is used for infections with gram-negative organisms, but may be neurotoxic and nephrotoxic.Protein Structure, Tertiary: 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.Protein Conformation: 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).Lipid A: Lipid A is the biologically active component of lipopolysaccharides. It shows strong endotoxic activity and exhibits immunogenic properties.Membranes: Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.Membrane Lipids: 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.Lipoproteins: Lipid-protein complexes involved in the transportation and metabolism of lipids in the body. They are spherical particles consisting of a hydrophobic core of TRIGLYCERIDES and CHOLESTEROL ESTERS surrounded by a layer of hydrophilic free CHOLESTEROL; PHOSPHOLIPIDS; and APOLIPOPROTEINS. Lipoproteins are classified by their varying buoyant density and sizes.Fimbriae, Bacterial: Thin, hairlike appendages, 1 to 20 microns in length and often occurring in large numbers, present on the cells of gram-negative bacteria, particularly Enterobacteriaceae and Neisseria. Unlike flagella, they do not possess motility, but being protein (pilin) in nature, they possess antigenic and hemagglutinating properties. They are of medical importance because some fimbriae mediate the attachment of bacteria to cells via adhesins (ADHESINS, BACTERIAL). Bacterial fimbriae refer to common pili, to be distinguished from the preferred use of "pili", which is confined to sex pili (PILI, SEX).Protein Binding: 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.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Protein Folding: Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Plasmids: 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.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Virulence Factors: Those components of an organism that determine its capacity to cause disease but are not required for its viability per se. Two classes have been characterized: TOXINS, BIOLOGICAL and surface adhesion molecules that effect the ability of the microorganism to invade and colonize a host. (From Davis et al., Microbiology, 4th ed. p486)Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Immunoblotting: Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.Salmonella typhimurium: A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.Membrane Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.Molecular Weight: The sum of the weight of all the atoms in a molecule.Neisseria meningitidis: A species of gram-negative, aerobic BACTERIA. It is a commensal and pathogen only of humans, and can be carried asymptomatically in the NASOPHARYNX. When found in cerebrospinal fluid it is the causative agent of cerebrospinal meningitis (MENINGITIS, MENINGOCOCCAL). It is also found in venereal discharges and blood. There are at least 13 serogroups based on antigenic differences in the capsular polysaccharides; the ones causing most meningitis infections being A, B, C, Y, and W-135. Each serogroup can be further classified by serotype, serosubtype, and immunotype.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Genes, Bacterial: The functional hereditary units of BACTERIA.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Mitochondrial Membranes: The two lipoprotein layers in the MITOCHONDRION. The outer membrane encloses the entire mitochondrion and contains channels with TRANSPORT PROTEINS to move molecules and ions in and out of the organelle. The inner membrane folds into cristae and contains many ENZYMES important to cell METABOLISM and energy production (MITOCHONDRIAL ATP SYNTHASE).Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Mutation: 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.Chlamydia trachomatis: Type species of CHLAMYDIA causing a variety of ocular and urogenital diseases.Cloning, Molecular: 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.Membranes, Artificial: Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.Detergents: Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.Haemophilus influenzae: A species of HAEMOPHILUS found on the mucous membranes of humans and a variety of animals. The species is further divided into biotypes I through VIII.Erythrocyte Membrane: The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.Neisseria gonorrhoeae: A species of gram-negative, aerobic bacteria primarily found in purulent venereal discharges. It is the causative agent of GONORRHEA.Bacterial Vaccines: Suspensions of attenuated or killed bacteria administered for the prevention or treatment of infectious bacterial disease.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Membrane Fluidity: The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.Chlamydophila psittaci: A genus of CHLAMYDOPHILA infecting primarily birds. It contains eight known serovars, some of which infect more than one type of host, including humans.Protein Sorting Signals: Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Pseudomonas aeruginosa: A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.Periplasmic Proteins: Proteins found in the PERIPLASM of organisms with cell walls.Recombinant Fusion Proteins: 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.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Cell Fractionation: Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.Mitochondria: Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)Mitochondrial Membrane Transport Proteins: Proteins involved in the transport of specific substances across the membranes of the MITOCHONDRIA.Bacterial Adhesion: Physicochemical property of fimbriated (FIMBRIAE, BACTERIAL) and non-fimbriated bacteria of attaching to cells, tissue, and nonbiological surfaces. It is a factor in bacterial colonization and pathogenicity.Epitopes: Sites on an antigen that interact with specific antibodies.Blood Bactericidal Activity: The natural bactericidal property of BLOOD due to normally occurring antibacterial substances such as beta lysin, leukin, etc. This activity needs to be distinguished from the bactericidal activity contained in a patient's serum as a result of antimicrobial therapy, which is measured by a SERUM BACTERICIDAL TEST.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Iron: A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.PeptidoglycanCell Line: Established cell cultures that have the potential to propagate indefinitely.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Moraxella (Branhamella) catarrhalis: Gram-negative aerobic cocci of low virulence that colonize the nasopharynx and occasionally cause MENINGITIS; BACTEREMIA; EMPYEMA; PERICARDITIS; and PNEUMONIA.Basement Membrane: A darkly stained mat-like EXTRACELLULAR MATRIX (ECM) that separates cell layers, such as EPITHELIUM from ENDOTHELIUM or a layer of CONNECTIVE TISSUE. The ECM layer that supports an overlying EPITHELIUM or ENDOTHELIUM is called basal lamina. Basement membrane (BM) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. BM, composed mainly of TYPE IV COLLAGEN; glycoprotein LAMININ; and PROTEOGLYCAN, provides barriers as well as channels between interacting cell layers.Solubility: The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Enterobactin: An iron-binding cyclic trimer of 2,3-dihydroxy-N-benzoyl-L-serine. It is produced by E COLI and other enteric bacteria.Siderophores: Low-molecular-weight compounds produced by microorganisms that aid in the transport and sequestration of ferric iron. (The Encyclopedia of Molecular Biology, 1994)Liposomes: 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.Ferrichrome: A cyclic peptide consisting of three residues of delta-N-hydroxy-delta-N-acetylornithine. It acts as an iron transport agent in Ustilago sphaerogena.Sequence Alignment: 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.Colicins: Bacteriocins elaborated by strains of Escherichia coli and related species. They are proteins or protein-lipopolysaccharide complexes lethal to other strains of the same species.Microscopy, Immunoelectron: Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.Mitochondrial Proteins: Proteins encoded by the mitochondrial genome or proteins encoded by the nuclear genome that are imported to and resident in the MITOCHONDRIA.Virulence: The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.Temperature: 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.Kinetics: The rate dynamics in chemical or physical systems.

Membrane deinsertion of SecA underlying proton motive force-dependent stimulation of protein translocation. (1/8526)

The proton motive force (PMF) renders protein translocation across the Escherichia coli membrane highly efficient, although the underlying mechanism has not been clarified. The membrane insertion and deinsertion of SecA coupled to ATP binding and hydrolysis, respectively, are thought to drive the translocation. We report here that PMF significantly decreases the level of membrane-inserted SecA. The prlA4 mutation of SecY, which causes efficient protein translocation in the absence of PMF, was found to reduce the membrane-inserted SecA irrespective of the presence or absence of PMF. The PMF-dependent decrease in the membrane-inserted SecA caused an increase in the amount of SecA released into the extra-membrane milieu, indicating that PMF deinserts SecA from the membrane. The PMF-dependent deinsertion reduced the amount of SecA required for maximal translocation activity. Neither ATP hydrolysis nor exchange with external SecA was required for the PMF-dependent deinsertion of SecA. These results indicate that the SecA deinsertion is a limiting step of protein translocation and is accelerated by PMF, efficient protein translocation thereby being caused in the presence of PMF.  (+info)

Cloning and characterisation of a novel ompB operon from Vibrio cholerae 569B. (2/8526)

The ompB operon of Vibrio cholerae 569B has been cloned and fully sequenced. The operon encodes two proteins, OmpR and EnvZ, which share sequence identity with the OmpR and EnvZ proteins of a variety of other bacteria. Although the order of the ompR and envZ genes of V. cholerae is similar to that of the ompB operon of E. coli, S. typhimurium and X. nematophilus, the Vibrio operon exhibits a number of novel features. The structural organisation and features of the V. cholerae ompB operon are described.  (+info)

Role of DnaK in in vitro and in vivo expression of virulence factors of Vibrio cholerae. (3/8526)

The dnaK gene of Vibrio cholerae was cloned, sequenced, and used to construct a dnaK insertion mutant which was then used to examine the role of DnaK in expression of the major virulence factors of this important human pathogen. The central regulator of several virulence genes of V. cholerae is ToxR, a transmembrane DNA binding protein. The V. cholerae dnaK mutant grown in standard laboratory medium exhibited phenotypes characteristic of cells deficient in ToxR activity. Using Northern blot analysis and toxR transcriptional fusions, we demonstrated a reduction in expression of the toxR gene in the dnaK mutant strain together with a concomitant increase in expression of a htpG-like heat shock gene that is located immediately upstream and is divergently transcribed from toxR. This may be due to increased heat shock induction in the dnaK mutant. In vivo, however, although expression from heat shock promoters in the dnaK mutant was similar to that observed in vitro, expression of both toxR and htpG was comparable to that by the parental strain. In both strains, in vivo expression of toxR was significantly higher than that observed in vitro, but no reciprocal decrease in htpG expression was observed. These results suggest that the modulation of toxR expression in vivo may be different from that observed in vitro.  (+info)

Role of Bordetella pertussis virulence factors in adherence to epithelial cell lines derived from the human respiratory tract. (4/8526)

During colonization of the respiratory tract by Bordetella pertussis, virulence factors contribute to adherence of the bacterium to the respiratory tract epithelium. In the present study, we examined the roles of the virulence factors filamentous hemagglutinin (FHA), fimbriae, pertactin (Prn), and pertussis toxin (PT) in the adherence of B. pertussis to cells of the human bronchial epithelial cell line NCI-H292 and of the laryngeal epithelial cell line HEp-2. Using B. pertussis mutant strains and purified FHA, fimbriae, Prn, and PT, we demonstrated that both fimbriae and FHA are involved in the adhesion of B. pertussis to laryngeal epithelial cells, whereas only FHA is involved in the adherence to bronchial epithelial cells. For PT and Prn, no role as adhesion factor was found. However, purified PT bound to both bronchial and laryngeal cells and as such reduced the adherence of B. pertussis to these cells. These data may imply that fimbriae play a role in infection of only the laryngeal mucosa, while FHA is the major factor in colonization of the entire respiratory tract.  (+info)

Functional activities and epitope specificity of human and murine antibodies against the class 4 outer membrane protein (Rmp) of Neisseria meningitidis. (5/8526)

Antibodies against the class 4 outer membrane protein (OMP) from Neisseria meningitidis have been purified from sera from vaccinees immunized with the Norwegian meningococcal group B outer membrane vesicle vaccine. The human sera and purified antibodies reacted strongly with the class 4 OMP in immunoblots, whereas experiments with whole bacteria showed only weak reactions, indicating that the antibodies mainly reacted with parts of the class 4 molecule that were not exposed. The purified human anti-class 4 OMP antibodies and the monoclonal antibodies (MAbs) were neither bactericidal nor opsonic against live meningococci. Three new MAbs against the class 4 OMP were generated and compared with other, previously described MAbs. Three linear epitopes in different regions of the class 4 OMP were identified by the reaction of MAbs with synthetic peptides. The MAbs showed no blocking effect on bactericidal activity of MAbs against other OMPs. However, one of the eight purified human anti-class 4 OMP antibody preparations, selected from immunoblot reactions among sera from 27 vaccinees, inhibited at high concentrations the bactericidal effect of a MAb against the class 1 OMP. However, these antibodies were not vaccine induced, as they were present also before vaccination. Therefore, this study gave no evidence that vaccination with a meningococcal outer membrane vesicle vaccine containing the class 4 OMP induces blocking antibodies. Our data indicated that the structure of class 4 OMP does not correspond to standard beta-barrel structures of integral OMPs and that no substantial portion of the OmpA-like C-terminal region of this protein is located at the surface of the outer membrane.  (+info)

The levels and bactericidal capacity of antibodies directed against the UspA1 and UspA2 outer membrane proteins of Moraxella (Branhamella) catarrhalis in adults and children. (6/8526)

The UspA1 and UspA2 proteins from Moraxella catarrhalis share antigenic epitopes and are promising vaccine candidates. In this study, the levels and bactericidal activities of antibodies in sera from healthy adults and children toward UspA1 and UspA2 from the O35E strain were measured. Human sera contained antibodies to both proteins, and the levels of immunoglobulin G (IgG) antibodies were age dependent. Adult sera had significantly higher titers of IgG than child sera (P < 0.01). The IgG3 titers to the UspA proteins were higher than the IgG1 titers in the adults' sera, while the IgG1 titers were higher than the IgG3 titers in the children's sera (P < 0.05). The IgG antibodies in the sera from 2-month-old children appeared to be maternally derived, since the mean titer was significantly higher than that in sera from 6- to 7-month-old children (P < 0.05). Serum IgA antibodies to both UspA1 and UspA2 were low during the first 7 months of age but thereafter gradually increased along with the IgG titers. Analysis of sera absorbed with UspA1 or UspA2 showed that the antibodies to UspA1 and UspA2 were cross-reactive with each other and associated with serum bactericidal activity. Examination of affinity-purified human antibodies confirmed that naturally acquired antibodies to UspA1 and UspA2 were bactericidal and cross-reactive. These results support using UspA1 and UspA2 in a vaccine to prevent M. catarrhalis infections.  (+info)

Expression of the plague plasminogen activator in Yersinia pseudotuberculosis and Escherichia coli. (7/8526)

Enteropathogenic yersiniae (Yersinia pseudotuberculosis and Yersinia enterocolitica) typically cause chronic disease as opposed to the closely related Yersinia pestis, the causative agent of bubonic plague. It is established that this difference reflects, in part, carriage by Y. pestis of a unique 9.6-kb pesticin or Pst plasmid (pPCP) encoding plasminogen activator (Pla) rather than distinctions between shared approximately 70-kb low-calcium-response, or Lcr, plasmids (pCD in Y. pestis and pYV in enteropathogenic yersiniae) encoding cytotoxic Yops and anti-inflammatory V antigen. Pla is known to exist as a combination of 32.6-kDa (alpha-Pla) and slightly smaller (beta-Pla) outer membrane proteins, of which at least one promotes bacterial dissemination in vivo and degradation of Yops in vitro. We show here that only alpha-Pla accumulates in Escherichia coli LE392/pPCP1 cultivated in enriched medium and that either autolysis or extraction of this isolate with 1.0 M NaCl results in release of soluble alpha and beta forms possessing biological activity. This process also converted cell-bound alpha-Pla to beta-Pla and smaller forms in Y. pestis KIM/pPCP1 and Y. pseudotuberculosis PB1/+/pPCP1 but did not promote solubilization. Pla-mediated posttranslational hydrolysis of pulse-labeled Yops in Y. pseudotuberculosis PB1/+/pPCP1 occurred more slowly than that in Y. pestis but was otherwise similar except for accumulation of stable degradation products of YadA, a pYV-mediated fibrillar adhesin not encoded in frame by pCD. Carriage of pPCP by Y. pseudotuberculosis did not significantly influence virulence in mice.  (+info)

Characterization of Moraxella (Branhamella) catarrhalis lbpB, lbpA, and lactoferrin receptor orf3 isogenic mutants. (8/8526)

Pathogenic members of the family Neisseriaceae produce specific receptors to acquire iron from their host's lactoferrin and transferrin. Recently, putative Moraxella catarrhalis lactoferrin receptor genes and a third open reading frame (lbpB, lbpA, and orf3) were cloned and sequenced. We describe the preliminary characterization of isogenic mutants deficient in LbpB, LbpA, or Orf3 protein.  (+info)

Journal Article: Small-Molecule Transport by CarO, an Abundant Eight-Stranded beta-Barrel Outer Membrane Protein from Acinetobacter Baumannii ...
TY - JOUR. T1 - A set of two monoclonal antibodies specific for the cell surface-exposed 39K major outer membrane protein of Haemophilus influenzae type b defines all strains of this pathogen. AU - Gulig, P. A.. AU - Frisch, C. F.. AU - Hansen, E. J.. PY - 1983. Y1 - 1983. N2 - Six murine plasma cell hybridomas producing monoclonal antibodies (mabs) directed against the 39,000-molecular-weight (39K) major outer membrane protein of Haemophilus influenzae type b were employed in the antigenic analysis of the 39K protein. The initial characterization of the mabs by radioimmunoprecipitation analysis showed that four of these mabs reacted with antigenic determinants of the 39K protein that are exposed on the bacterial cell surface and accessible to antibody. The other two mabs reacted with antigenic determinants of the 39K protein that are either not exposed on the H. influenzae type b cell surface or not accessible to antibody (internal determinants). A total of 126 clinical isolates of H. ...
A vast number of studies have been completed on the virulence determinants of Yersinia spp.; however, the focus of many of these studies has been on the virulence plasmid and the plasmid-encoded Type three secretion system. Nevertheless, many chromosomal genes whose products are directly involved in virulence have also been identified. Some of these critical virulence determinants are outer membrane proteins. Outer membrane proteins of Gram-negative bacteria often have important physiological roles; however, some have also been found to be important for pathogenesis. In this thesis, we investigated two Yersinia. pestis outer membrane proteins, Ail and OmpA, and their roles in virulence. We provide evidence that Y. pestis Ail is a highly expressed outer membrane protein that is absolutely essential for Y. pestis to resist the killing action of the complement system present in human blood and tissues, as well as the blood and tissues of other mammalian hosts. Furthermore, Ail was important for ...
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The toxR gene of Vibrio cholerae encodes a transmembrane, DNA-binding protein that activates transcription of the cholera toxin operon and a gene (tcpA) for the major subunit of a pilus colonization factor. We constructed site-directed insertion mutations in the toxR gene by a novel method employing the chromosomal integration of a mobilizable suicide plasmid containing a portion of the toxR coding sequence. Mutants containing these new toxR alleles had an altered outer membrane protein profile, suggesting that two major outer membrane proteins (OmpT and OmpU) might be under the control of toxR. Physiological studies indicated that varying the concentration of the amino acids asparagine, arginine, glutamate, and serine caused coordinate changes in the expression of cholera toxin, TcpA, OmpT, and OmpU. Changes in the osmolarity of a tryptone-based medium also produced coordinate changes in the expression of these proteins. Other environmental signals (temperature and pH) had a more pronounced ...
Drugs and certain proteins are transported across the membranes of Gram-negative bacteria by energy-activated pumps. The outer membrane component of these pumps is a channel that opens from a sealed resting state during the transport process. We describe two crystal structures of the Escherichia coli outer membrane protein TolC in its partially open state. Opening is accompanied by the exposure of three shallow intraprotomer grooves in the TolC trimer, where our mutagenesis data identify a contact point with the periplasmic component of a drug efflux pump, AcrA. We suggest that the assembly of multidrug efflux pumps is accompanied by induced fit of TolC driven mainly by accommodation of the periplasmic component.,br/, ...
Cloning and characterization of the major outer membrane protein gene (ompH) of Pasteurella multocida X-73.: The major outer membrane protein (OmpH) of Pasteure
PCR methods.Holland et al. (31) developed a major outer membrane protein (MOMP)-based PCR test that could identify three species of Chlamydia (C. trachomatis, C. pneumoniae, and C. psittaci) using three primer pairs and one restriction enzyme digestion.. Rasmussen et al. (73) described a protocol that amplifies a conserved genus-specific target of the chlamydial MOMP gene followed by restriction enzyme digestion for species identification.. Watson et al. (89) developed a PCR assay based on amplification of the 60-kDa cysteine-rich outer membrane protein genes of C. psittaci, C. pneumoniae, and C. trachomatis, followed by species differentiation with four restriction endonuclease digestion enzymes. Similarly, Tjhie et al. (84) developed a general PCR with a target within the MOMP gene. Subsequent species-specific differentiation of C. trachomatis, C. pneumoniae, and C. psittaciwas performed by hybridization of the amplified PCR product with internal probes.. Several of the early methods described ...
Khandelwal and colleagues succeeded in identifying the insecticidal factor. The active component was found in a large complex normally associated with the bacterial outer membrane, and was also present in or on outer membrane vesicles (OMVs) released from the bacterial surface, says Khandelwal. They then searched through OMV components and identified a small (17 kDa) toxic protein. When purified, this protein was toxic to cultured larval cells and directly killed H. armigera larvae. Gene cloning and sequencing showed this protein is related to a class of bacterial outer membrane proteins that form protrusions, called pili or fimbriae, which often help bacteria attach to host cells during infection. Similar to pili proteins, the purified 17 kDa protein self-associated to form oligomers, each of which was connected to the next by a strand. Most importantly, the recombinant 17 kDa protein killed H. armigera larvae, demonstrating its potential as a biological control agent in a world desperately in ...
Dispensable loops shield the functionally-important extracellular loops of the essential Gram-negative bacterial outer membrane protein LptD from antibody interference.
p>The checksum is a form of redundancy check that is calculated from the sequence. It is useful for tracking sequence updates.,/p> ,p>It should be noted that while, in theory, two different sequences could have the same checksum value, the likelihood that this would happen is extremely low.,/p> ,p>However UniProtKB may contain entries with identical sequences in case of multiple genes (paralogs).,/p> ,p>The checksum is computed as the sequence 64-bit Cyclic Redundancy Check value (CRC64) using the generator polynomial: x,sup>64,/sup> + x,sup>4,/sup> + x,sup>3,/sup> + x + 1. The algorithm is described in the ISO 3309 standard. ,/p> ,p class="publication">Press W.H., Flannery B.P., Teukolsky S.A. and Vetterling W.T.,br /> ,strong>Cyclic redundancy and other checksums,/strong>,br /> ,a href="http://www.nrbook.com/b/bookcpdf.php">Numerical recipes in C 2nd ed., pp896-902, Cambridge University Press (1993),/a>),/p> Checksum:i ...
Bacterial OMPs are synthesized in the cytosol as precursor proteins with an amino‐terminal signal sequence that guides the proteins to the Sec machinery for crossing the inner membrane and is cleaved off in the periplasm. Periplasmic chaperones then escort OMPs through the aqueous periplasmic space in a partly unfolded state. On reaching the outer membrane, OMPs assemble into a β‐barrel structure and insert into the outer membrane with the help of the BAM complex. The bacterial OMP insertion pathway can be compared to the assembly pathway of MBOMPs from the mitochondrial intermembrane space into the outer membrane. MBOMPs are synthesized in the cytosol and imported into the intermembrane space by the outer membrane translocator TOM40. The subsequent chaperone‐mediated escort across the intermembrane space and insertion into the outer membrane by the TOB complex is similar to the OMP assembly process. Notably, the BAM and TOB complexes share the homologous β‐barrel proteins BamA and ...
Author: Anbazhagan, V. et al.; Genre: Journal Article; Published in Print: 2008-06-10; Title: Incorporation of outer membrane protein OmpG in lipid membranes: protein−lipid interactions and β-barrel orientation.
Allison, Heather, Smith, Darren, Loughnane, Paul, Saunders, Jon and McCarthy, Alan (2004) Identification of an outer membrane protein that enables infection of Escherichia coli by Shiga toxin encoding bacteriophage. In: 155th Society for General Microbiology Meeting, September 2004, Dublin, Ireland. Full text not available from this repository. (Request a copy ...
Download Free Full-Text of an article EXTRACTION OF THE OUTER MEMBRANE PROTEINS OF H. PYLORI AND EVALUATION OF THEIR PRESENCE IN STOOL OF THE INFECTED INDIVIDUALS
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We compare several spectral domain based clustering methods for partitioning protein sequence data. The main instrument for this exercise is the spectral density ratio model, which specifies that the logarithmic ratio of two or more unknown spectral density functions has a parametric linear combination of cosines. Maximum likelihood inference is worked out in detail and it is shown that its output yields several distance measures among independent stationary time series. These similarity indices are suitable for clustering time series data based on their second order properties. Other spectral domain based distances are investigated as well; and we compare all methods and distances to the problem of producing segmentations of bacterial outer membrane proteins consistent with their transmembrane topology. Protein sequences are transformed to time series data by employing numerical scales of physicochemical parameters. We also present interesting results on the prediction of transmembrane ...
Subunit Of Both The ERMES And The SAM Complex; Component Of ERMES Complex Which Acts As A Molecular Tether Between The Mitochondria And The ER, Necessary For Efficient Phospholipid Exchange Between Organelles And For Mitophagy; SAM/TOB Complex Component That Functions In The Assembly Of Outer Membrane Beta-barrel Proteins; Involved In Mitochondrial Inheritance And Morphology; ERMES Complex Is Often Co-localized With Peroxisomes And Concentrated Areas Of Pyruvate Dehydrogenase
The mitochondrial outer membrane plays a crucial role in the biogenesis, inheritance and dynamics of the organelle and forms the functional and signaling link between mitochondria and the rest of the eukaryotic cell. This membrane contains a diverse set of proteins that are synthesized in the cytosol and harbor signals that are essential for their subsequent import into mitochondria. We investigate the molecular mechanisms by which the various mitochondrial outer membrane proteins are targeted to mitochondria, inserted into the outer membrane and assembled into functional complexes within the membrane. In addition, we study the mechanisms and components that regulate lipids homeostasis in mitochondria. For our studies we use both yeast and mammalian tissue cultures as experimental systems.. ...
The mitochondrial outer membrane plays a crucial role in the biogenesis, inheritance and dynamics of the organelle and forms the functional and signaling link between mitochondria and the rest of the eukaryotic cell. This membrane contains a diverse set of proteins that are synthesized in the cytosol and harbor signals that are essential for their subsequent import into mitochondria. We investigate the molecular mechanisms by which the various mitochondrial outer membrane proteins are targeted to mitochondria, inserted into the outer membrane and assembled into functional complexes within the membrane. In addition, we study the mechanisms and components that regulate lipids homeostasis in mitochondria. For our studies we use both yeast and mammalian tissue cultures as experimental systems.. ...
Nair, S A and Rathinavelan, Thenmalarchelvi (2015) Bidirectional water conductivity of E.coli outer membrane lectin(Wzi) is regulated by surface aromatic residues and luminal hydrophobic plug. In: National Symposium on Biophysics and Golden Jubilee Meeting of Indian Biophysical Society, Center for Interdisciplinary Research in Basic Sciences, 14-17 February 2015, New Delhi, India. Full text not available from this repository. (Request a copy ...
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Bacterial proteins with MCE domains were first described as being important for Mammalian Cell Entry. More recent evidence suggests they are components of lipid ABC transporters. In Escherichia coli, the single-domain protein MlaD is known to be part of an inner membrane transporter that is important for maintenance of outer membrane lipid asymmetry. Here we describe two multi MCE domain-containing proteins in Escherichia coli, PqiB and YebT, the latter of which is an orthologue of MAM-7 that was previously reported to be an outer membrane protein. We show that all three MCE domain-containing proteins localise to the inner membrane. Bioinformatic analyses revealed that MCE domains are widely distributed across bacterial phyla but multi MCE domain-containing proteins evolved in Proteobacteria from single-domain proteins. Mutants defective in mlaD, pqiAB and yebST were shown to have distinct but partially overlapping phenotypes, but the primary functions of PqiB and YebT differ from MlaD. Complementing
Syma Khalid (Investigator) Many bacteria have an outer membrane which is the interface between the cell and its environment. The components of this membrane are well studied at an individual level, but there is a need to model and understand the outer membrane as a whole. In this project we aim to develop such a model of a bacterial outer membrane, linking computer simulations of the component molecules through to a more systems biology approach to modelling the outer membrane as a whole. Such an approach to modelling an OM must be multi-scale i.e. it must embrace a number of levels ranging from atomistic level modelling of e.g. the component proteins through to higher level agent-based modelling of the interplay of multiple components within the outer membrane as a whole. The different levels of description will be integrated to enable predictive modelling in order to explore the roles of outer membrane changes in e.g. antibiotic resistance.. ...
The relationship between iron acquisition and microbial pathogenesis (1, 38, 51, 84, 104) underscores the importance of the role of TonB in cell envelope physiology. Passage of ferric complexes through the OM requires TonB activity, and one theory of this requirement is that TonB participates in transport energetics by capturing proton motive force from the IM (where its N terminus resides) and distributing it to the OM transporters (14, 23, 76, 82, 95). According to the "shuttle" model of TonB action, it associates with the IM proteins ExbB and ExbD (42, 56), acquires proton motive force-generated energy by an unknown structural transition, and transmits (15) or physically transports (55, 57) the energy across the periplasm to the OM. The proposed interaction of "energized" TonB with OM proteins entails recognition of ligand-bound receptors and release of the stored force to them by protein-protein interactions between the C-terminal residues of TonB and the TonB box sequence of the LGP (76, ...
We describe a lesion, lamB701-708, affecting the hydrophilic portion of the lambda receptor signal sequence. The C to A transversion of the sixth codon of the signal sequence changes a positively charged arginine to a neutral serine. The phenotype conferred by this alteration is unique among previously described signal sequence mutations. The results suggest an essential role for the charged amino acids of the hydrophilic segment in the initial interaction between a nascent secreted protein and a membrane export site. The results further suggest that synthesis of lambda receptor is coupled to its export ...
The outer membrane of most Gram-negative bacteria is made up of LPS, and in nearly all bacteria that contain LPS it is essential for the life of the organism. The lipid portion of this molecule, lipid A, also known as endotoxin, is a potent activator of the innate immune response. More than 50 genes are required to synthesize LPS and assemble it at the cell surface. Enormous progress has been made in elucidating the structure and biosynthesis of LPS, but until recently the cellular components required for its transport from its site of synthesis in the inner membrane to its final cellular location at the cell surface remained elusive. Here we describe the identification of a protein complex that functions to assemble LPS at the surface of the cell. This complex contains two proteins: Imp, already identified as an essential outer-membrane protein implicated in LPS assembly; another protein, RlpB, heretofore identified only as a rare lipoprotein. We show that RlpB is also essential for cell viability and
The [email protected] Centre provides a platform for research students to deposit their Ph.D. theses and make it available to the entire scholarly community in open access. Shodhganga Mirror Site ...
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CPn0444 is similar to CT871, CT874, CT413, CT812, CT872, CT414, CT412, CT870, CT869, and CT456. They are predicted outer membrane proteins. CT871 is a predicted pmpG outer membrane protein G. Residues 470-1407 are 28% similar to CT871 ...
22, Table 33. Their outer membrane proteins contain cross- reactive antigens and surface-exposed epitopes that are species specific.
An outer membrane protein T (OmpT) could play a vital role in the pathogenesis of the neonatal meningitis Escherichia coli (NMEC) in human and animals. However, whether ompT plays a role in avian pathogenic E. coli (APEC) infection remains unclear. In this study we evaluated the potential of ompT in APEC pathogenesis. An ompT gene was deleted from APEC mutant strain (TW-XM) was constructed and cha ...
sample_1: KpOmpA transmembrane domain, [U-13C; U-15N; U-2H], 1 mM; DHPC 300 mM; NaH2PO4 20 mM; NaCl 100 mM; H2O 90%; D2O 10%. sample_2: KpOmpA transmembrane domain, [U-13C; U-15N; U-2H]/[L,V,I(delta1)-13CH3], 1 mM; DHPC 300 mM; NaH2PO4 20 mM; NaCl 100 mM; H2O 90%; D2O 10%. sample_3: KpOmpA transmembrane domain, [U-15N; 10% 13C], 1 mM; DHPC 300 mM; NaH2PO4 20 mM; NaCl 100 mM; H2O 90%; D2O 10%. sample_4: KpOmpA transmembrane domain, [U-13C; U-15N; U-2H]/[L,V,I(delta1)-13CH3], 1 mM; DHPC 300 mM; NaH2PO4 20 mM; NaCl 100 mM; H2O 90%; D2O 10%. sample_conditions_1: ionic strength: 0.1 M; pH: 6.5; pressure: 1 atm; temperature: 313 K ...
Michalik, M.; Orwick-Rydmark, M.; Habeck, M.; Alva, V.; Arnold, T.; Linke, D.: An evolutionarily conserved glycine-tyrosine motif forms a folding core in outer membrane proteins. PLoS One 12 (8) (2017 ...
View Notes - cells2 from BIOL 20204 at TCU. II. The Cell- Basic Unit of Life A. Cell or Plasma membrane-found @ outer surface of cell 1. Structure i. Thickness-75 ancryms=3/10,000,000 ii. Fluid
A murine immunoglobulin G monoclonal antibody (MAb) raised against outer membrane vesicles of Moraxella catarrhalis 035E was shown to bind to a surface-exposed epitope of a major outer membrane protein of this organism. This outer membrane protein, which had an apparent molecular weight of approximately 80,000 in sodium dodecyl sulfate-polyacrylamide gels, was designated CopB. MAb 10F3, reactive with CopB, bound to a majority (70%) of M. catarrhalis strains tested. More importantly, mice passively immunized with MAb 10F3 exhibited an enhanced ability to clear a bolus challenge of M. catarrhalis from their lungs, a result which suggested that CopB might have potential as a vaccine candidate. The M. catarrhalis gene encoding CopB was cloned in Escherichia coli, and nucleotide sequence analysis of the copB gene indicated that the CopB protein was synthesized with a leader peptide, a finding confirmed by N-terminal amino acid sequence analysis of the mature CopB protein purified from M. catarrhalis ...
Analysis of major outer membrane protein (MOMP) profiles of various meningococci by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE) revealed the presence of 0 to 2 low-molecular-weight, heat-modifiable MOMPs (molecular weight, 25,000 to 32,000) and 1 to 3 high-molecular-weight MOMPs (molecular weight, 32,000 to 46,000). Heat modifiability was investigated by comparing MOMP profiles after heating in SDS solutions at 100°C for 5 min or at 40°C for 1 h. Low-molecular-weight MOMPs shifted to higher apparent molecular weights after being heated at 100°C. Heat modifiability of high-molecular-weight MOMPs varied among strains; whenever modified these proteins shifted to lower apparent molecular weights after complete denaturation. Variability of low-molecular-weight, heat-modifiable MOMPs was demonstrated when MOMP profiles were compared of (i) isolates from index cases and associated cases and carriers among contacts, (ii) different isolates from the same individual, and ...
The signal peptide of the outer membrane lipoprotein (OMLP) of Escherichia coli was shown to be capable of promoting protein translocation across mammalian microsomal membranes in vitro. We assayed translocation of a fusion protein containing the OMLP signal peptide and nine amino acids of OMLP fused in frame to beta-lactamase. The efficiency with which the mammalian translocation machinery recognizes and accepts the OMLP signal peptide as substrate is indistinguishable from that of mammalian secretory proteins. Upon translocation mammalian signal peptidase processes the pre-OMLP-beta-lactamase protein at different sites than are utilized in vivo by E. coli OMLP signal peptidase (signal peptidase II) but that can be predicted as mammalian signal peptidase cleavage sites. Mutants in the OMLP signal peptide were tested for their ability to promote translocation of the fusion protein in this assay system. It has been shown previously that mutants in the positively charged amino acids at the amino ...
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Part of the outer membrane protein assembly complex, which is involved in assembly and insertion of beta-barrel proteins into the outer membrane. Constitutes, with BamD, the core component of the assembly machinery.
The availability of genome sequences and the corresponding translated protein databases have enabled studies on the meningococcal proteome, particularly the detailed composition of outer membrane fractions. In early studies, Frasch and colleagues [20] were able to distinguish only five major classes of proteins in outer membrane preparations from meningococci. Subsequently, additional proteins were identified that were present in lower amounts or only expressed when the bacteria had been grown under nutrient limitation (reviewed in [21]). The total number of proteins identified in outer membrane preparations remained relatively few until the development of more sensitive proteomic methods. This combined with the availability of the translated genome sequences has enabled much more detailed study of outer membrane preparations and the vesicle/vaccine preparations derived from them by deoxycholate extraction. One-dimensional SDS-PAGE of an OMV vaccine preparation followed by tandem mass ...
Outer membrane porin D is a protein family containing bacterial outer membrane porins which are involved in transport of cationic amino acids, peptides, antibiotics and other compounds. It was also described as having some serine protease activity. However many of these proteins are not peptidases and are classified as non-peptidase homologues as they either have been found experimentally to be without peptidase activity, or lack amino acid residues that are believed to be essential for the catalytic activity of peptidases in the S43 family. Yoshihara E, Yoneyama H, Ono T, Nakae T (June 1998). "Identification of the catalytic triad of the protein D2 protease in Pseudomonas aeruginosa". Biochem. Biophys. Res. Commun. 247 (1): 142-5. doi:10.1006/bbrc.1998.8745. PMID 9636669. This article incorporates text from the public domain Pfam and InterPro ...
No information on the cytokine profile to be used as a marker of Campylobacter jejuni infection protection. For this study, we used the outer membrane protein (MOMP [Pora]) as a vaccine for the protection and spleen cell cytokine as a marker of protection. We cloned and expressed Pora from C. jejuni111 and mice immunized with intraperitoneal route. Subsequently, the mice orally challenged with C. jejuni 111. live vaccine-induced protection as evidenced by a decrease in fecal excretion C. jejuni111. Cytokines were measured in vitro after stimulation of spleen cells with MOMP. Levels of pro-inflammatory cytokines, IL-12, TNF-α, IL-17A and IL-17F are similar in the control and test mice. Levels of pro-inflammatory cytokines, IL-2 and IFN-γ were higher in mice than in control mice test, and the level of pro-inflammatory cytokines, IL-8 and IL-1β was higher in the test mice than in control mice. In between the two anti-inflammatory cytokines, the same level of IL-10 but higher for IL-4 in the test ...
The Tar chemoreceptor of Escherichia coli is a membrane-bound sensory protein that facilitates bacterial chemotaxis in response to aspartate. The EnvZ molecule has a membrane topology similar to Tar and is a putative osmosensor that is required for osmoregulation of the genes for the major outer membrane porin proteins, OmpF and OmpC. The cytoplasmic signaling domain of Tar was replaced with the carboxyl portion of EnvZ, and the resulting chimeric receptor activated transcription of the ompC gene in response to aspartate. The activation of ompC by the chimeric receptor was absolutely dependent on OmpR, a transcriptional activator for ompF and ompC. ...
Gonorrheal urethritis was induced in three males by intraurethral instillation of predominantly pilus+ protein II- gonococci. Virtually all gonococci reisolated from the infected men exhibited protein II+ phenotype. The reisolated gonococci expressed five distinct outer membrane protein II species. Protein IIc+ organisms predominated in urines of all three subjects, but variants expressing this particular protein II were rarely spawned in vitro by input organisms. Protein IIc+ gonococci appeared early in one mans infection; they were joined later by variants that displayed eight other protein II phenotypes, including protein II-. These results show that input protein II- gonococci are supplanted by protein IIc+ variants during incipient gonorrheal urethritis. As infection progresses, a broader variety of protein II+ variants appears. ...
Looking for online definition of outer membrane in the Medical Dictionary? outer membrane explanation free. What is outer membrane? Meaning of outer membrane medical term. What does outer membrane mean?
PubMed journal article Export of the outer membrane lipoprotein is defective in secD, secE, and secF mutants of Escherichia col were found in PRIME PubMed. Download Prime PubMed App to iPhone or iPad.
Bacteria outer membrane lipoprotein I: vaccine candidate; antigenically cross-reacts with all serotype strains of the International Antigenic Typing Scheme; amino acid sequence given in first source
Genome analysis identified a large number of genes that would enable utilization of dilute carbon sources and provides a comprehensive picture of the strategies used by C. crescentus for survival in nutrient-limiting conditions. Unlike E. coli and Vibrio cholerae, C. crescentus has no OmpF-type outer membrane porins that allow the passive diffusion of hydrophilic substrates across the outer membrane. However, it does possess 65 members of the family of TonB-dependent outer membrane channels that catalyze energy-dependent transport across the outer membrane. This is more than any other organism thus far characterized, with the next highest being 34 in Pseudomonas aeruginosa (32), and with no other sequenced proteobacteria possessing more than 10. C. crescentus has substantially fewer cytoplasmic membrane transporters relative to genome size than either E. coli or V. cholerae (33). Given C. crescentus low nutrient habitat, it is surprising that PTS or ATP-binding cassette domain transporters, ...
A mutant variant of a septicemic Escherichia coli strain (L3) isolated from an outbreak in chickens was constructed by the insertion of TnphoA transposon. Seven mutant derivatives were analyzed regarding the pathogenicity. Two of them (XP2, XP4) were less pathogenic in the one-day-old chick pathogenicity assay. The expression of several outer membrane proteins of mutant XP2 strain was suppressed, and strain XP4 had a 47.8(kDa) protein that was not expressed. None of these proteins was correlated to the iron-acquisition system. Mutant XP2 could have suppression of a regulatory protein responsible for the expression of other proteins not related to pathogenicity but important for the rapid bacterial growth, while mutant XP4 did not express a 47.8(kDa) protein. We propose that the 47.8(kDa) protein could be associated to the pathogenicity process of Escherichia coli strains responsible for septicemia in poultry ...
The membrane assembly of outer membrane proteins is more complex than that of transmembrane helical proteins owing to the intervention of many charged and polar residues in the membrane. Accordingly, the predictive accuracy of transmembrane beta strands is considerably lower than that of transmembrane alpha helices. In this paper we develop a set of conformational parameters for membrane spanning beta strands. We formulate an algorithm to predict the transmembrane beta strands in the family of bacterial porins based on the conformational parameters and surrounding hydrophobicities of amino acid residues. A Fortran program has been developed which takes the amino acid sequence as the input file and gives the predicted transmembrane beta strand as output. The present method predicts at an accuracy level of 82% for all the bacterial porins considered.
The susceptibility of the E. coli B strain to a variety of stressful conditions and antibiotics revealed by PM tests (Figure S3 in Additional file 1) can be explained by several observations (Figure 5). First, differences in the composition of the LPS core and expression of outer membrane proteins may influence the permeability and integrity of the cell envelope. B strains produce more OmpF porin than K-12 strains because the B genome lacks micF, which post-transcriptionally prevents production of OmpF [24]. This is further supported by the transcriptome data showing high levels of ompF expression in the B strain and high expression of ompC and ompA in the K-12 strain (Figure 4). These observations were also consistent with results of proteome analysis of the outer membrane fractions (Figure S2B in Additional file 1). Noxious agents such as antibiotics and bile acids diffuse more easily through OmpF than OmpC because the former produces a channel with a larger pore size [25]. Second, synthesis ...
Protein TonB; Interacts with outer membrane receptor proteins that carry out high-affinity binding and energy dependent uptake into the periplasmic space of specific substrates. It could act to transduce energy from the cytoplasmic membrane to specific energy- requiring processes in the outer membrane, resulting in the release into the periplasm of ligands bound by these outer membrane proteins (249 aa ...
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Motivation: Transmembrane beta-barrels exist in the outer membrane of gram-negative bacteria as well as in chloroplast and mitochondria. They are often involved in transport processes and are promising antimicrobial drug targets. Structures of only a few beta-barrel protein families are known. Therefore, a method that could automatically generate such models would be valuable. The symmetrical arrangement of the barrels suggests that an approach based on idealized geometries may be successful. Results: Here, we present tobmodel; a method for generating 3D models of beta-barrel transmembrane proteins. First, alternative topologies are obtained from the BOCTOPUS topology predictor. Thereafter, several 3D models are constructed by using different angles of the beta-sheets. Finally, the best model is selected based on agreement with a novel predictor, ZPRED3, which predicts the distance from the center of the membrane for each residue, i.e. the Z-coordinate. The Z-coordinate prediction has an average ...
Specific assembly proteins are required for the folding and integration of autotransporters into the outer membrane. Employing x-ray crystallography, the authors of the study decoded the atomic structure of the autotransporter assembly protein TamA of the intestinal bacterium Escherichia Coli.. "The protein TamA", explains Fabian Gruss, first author and recipient of a Werner-Siemens PhD fellowship, "also forms a barrel with a pore. The pore is closed to the outside by a lid but a particular kink in the barrel wall provides a gate for autotransporter substrates." When an unfolded autotransporter is delivered, TamA hooks onto one end of the substrate polypeptide chain and integrates it step by step via the gate into its own barrel structure. The TamA barrel is thus expanded; the pore widens and opens such that passenger substrates traverse to the exterior. The assembly process ends when TamA releases the autotransporter into the surrounding membrane. "The autotransporter insertion mechanism was ...
Structural relatedness of enteric bacterial porins assessed with monoclonal antibodies to Salmonella typhimurium OmpD and OmpC.: The immunochemistry and structu
The periplasm (the space between the inner and outer membranes of bacteria) is the site of activation of the periplasmic stress response. Like the cytosolic stress response and the eukaryotic endoplasmic and cytosolic stress responses, unfolded proteins trigger a transcriptional activation profile that allows cells to produce more chaperones and protein-folding agents (see Young and Hartl). Although, the periplasmic stress response is fairly well characterized, the sensor that initiates the process has remained elusive. The response consists of activation of the protease DegS, which cleaves transmembrane protein RseA, which then releases the transcription factor σE to allow the activation of stress response genes. Walsh et al. show that DegS is inhibited by its PDZ domain and that binding of the PDZ domain toYQF motifs of outer membrane protein porins activates the protease. Bacteria expressing DegS lacking the PDZ domain showed increased σE activity. Using an oriented peptide library, a ...
The outer membrane (OM) of Gram-negative pathogenic bacteria represents a platform for the secretion and presentation of surface-localized virulence factors. Th...
1GFN: Structural and functional characterization of OmpF porin mutants selected for larger pore size. I. Crystallographic analysis.
The more outer-membrane protein genes that can be expressed, the higher the chance the organism can avoid being recognized by ... Molecular interactions between bacterial symbionts and their hosts Cell, 126 (2006), pp. 453-465 Mavromatis, K.; Doyle, C. K.; ... With a higher range of outer-membrane proteins, the parasite can evade the immune system of the host more effectively and ... The evolutionary changes in the outer membrane proteins have led to the emergence of new strains which can infect a larger ...
The membrane channel is formed by an antiparallel beta-barrel. Maltoporin is a trimeric channel on the bacterial outer membrane ... Maltoporins (or LamB porins) are a family of outer membrane proteins. Maltoporin forms a trimeric structure which facilitates ... the diffusion of maltodextrins across the outer membrane of Gram-negative bacteria. ...
... s are a family of outer bacterial membrane proteins. These are anion-specific porins, the binding site ...
... or resistance to diffusion across the bacterial outer membrane.[11] Unlike imipenem, it is stable to dehydropeptidase-1, so can ... In general, resistance arises due to mutations in penicillin-binding proteins, production of metallo-β-lactamases, ... It inhibits bacterial cell wall synthesis like other β-lactam antibiotics. In contrast to other beta-lactams, it is highly ... Meropenem, sold under the brandname Merrem among others, is a broad-spectrum antibiotic used to treat a variety of bacterial ...
... coli where the inner membrane ABC transporter HlyB interacts with an inner membrane fusion protein HlyD and an outer membrane ... some bacterial ABC proteins are also involved in the regulation of several physiological processes. In bacterial efflux systems ... a membrane fusion protein (MFP), and an outer membrane factor (OMF). An example is the secretion of hemolysin (HlyA) from E. ... roles of membrane structure and electrostatics in lipid-protein and protein-protein interactions". Biochimica et Biophysica ...
... is an evolutionarily conserved domain of bacterial outer membrane proteins. This domain consists ... "The Borrelia afzelii outer membrane protein BAPKO_0422 binds human factor-H and is predicted to form a membrane-spanning β- ... Nair MK, Venkitanarayanan K, Silbart LK, Kim KS (May 2009). "Outer membrane protein A (OmpA) of Cronobacter sakazakii binds ... "Structure of the outer membrane protein A transmembrane domain". Nature Structural Biology. 5 (11): 1013-7. doi:10.1038/2983. ...
... s (KdgM) are a family of outer bacterial membrane proteins from Dickeya dadantii. The ...
... the ABC protein, membrane fusion protein (MFP), and outer membrane protein (OMP)[specify]. This secretion system transports ... Kuehn, M. J.; Kesty, N. C. (2005). "Bacterial outer membrane vesicles and the host-pathogen interaction". Genes & Development. ... the formation of outer membrane vesicles.[8][9] Portions of the outer membrane pinch off, forming spherical structures made of ... In a channel transupport system, several proteins form a contiguous channel traversing the inner and outer membranes of the ...
The comet forms in a polar manner and aids the bacterial migration to the host cell's outer membrane. Gelsolin, an actin ... It induces directed polymerization of actin by the ActA transmembrane protein, thus pushing the bacterial cell around. L. ... Abrishami S. H.; Tall B. D.; Bruursema T. J.; Epstein P. S.; Shah D. B. (1994). "Bacterial adherence and viability on cutting ... Laine R. O.; Phaneuf K. L.; Cunningham C. C.; Kwiatkowski D.; Azuma T.; Southwick F. S. (1 August 1998). "Gelsolin, a protein ...
The filled capsids are then coated with the nucleocapsid protein P8, and then outer membrane proteins somehow attract bacterial ... Fusion of the viral envelope with the bacterial outer membrane is facilitated by the phage protein, P6. The muralytic ( ... and the nucleocapsid enters the cell coated with the bacterial outer membrane. A copy of the sense strand of the large genome ... The cytosol then bursts forth, disrupting the outer membrane, releasing the phage. The bacterium is killed by this lysis. RNA- ...
The two inner membranes are called the outer (OEM) and inner envelope membrane (IEM) and are derived from the plastid envelope ... Within the apicoplast's membrane is a 35 kb long circular DNA strand that codes for approximately 30 proteins, tRNAs and some ... Particles suspected to be bacterial ribosomes are present. The plastid, at least in the Plasmodium species, also contains " ... The apicoplast is surrounded by four membranes within the outermost part of the endomembrane system. Apicoplasts are a relict, ...
Bos, Martine P.; Robert, Viviane; Tommassen, Jan (2007). «Biogenesis of the Gram-Negative Bacterial Outer Membrane». Annual ... The recombinant expression systems for structure determination of eukaryotic membrane proteins». Protein & Cell 5 (9): 658. doi ... Sellemembranar kan ha mange protein knytte til seg, og det har vore estimert at 30 % av dei proteinkodande gena i ... Wood, I. Stuart; Trayhurn, Paul (2007). «Glucose transporters (GLUT and SGLT): Expanded families of sugar transport proteins» ( ...
This protein is involved in the pathway LPS O-antigen biosynthesis, which is part of Bacterial outer membrane biogenesis. ... This terminal modification is essential for export of the O-antigen across the inner membrane. WbdD is also required for ...
Hritonenko V, Stathopoulos C (2007). "Omptin proteins: an expanding family of outer membrane proteases in Gram-negative ... protein a, Pla, OmpT) are a family of bacterial proteases. They are aspartate proteases, which cleave peptides with the use of ... Found in the outer membrane of gram-negative enterobacteria such as Shigella flexneri, Yersinia pestis, Escherichia coli, and ... Omptins consist of a widely conserved beta barrel spanning the membrane with 5 extra-cellular loops. These loops are ...
... a lipoprotein which may form a channel in the bacterial outer membrane. Wzb - a cytoplasmic regulatory phosphatase which ... The CPS operon is likely transcriptionally regulated by the Rcs (regulation of capsule synthesis) proteins. Reduced levels of ... Wzc - a tyrosine kinase found in the bacterial inner membrane. Participates in polymerization of capsule polysaccharides. Wzx ... The CPS operon contains genes which code for the following proteins: Wza - ...
... (the tsx gene of Escherichia coli) is an outer membrane protein, Tsx, which constitutes the receptor ... The protein contains 294 amino acids, the first 22 of which are characteristic of a bacterial signal sequence peptide. Tsx ... which encodes a nucleoside-specific channel-forming protein (Tsx) in the outer membrane of Escherichia coli". Gene. 96 (1): 59- ... shows no significant similarities to general bacterial porins. Bremer E, Martinussen J, Middendorf A, Valentin-Hansen P (1990 ...
Protein TolC, the outer membrane component of a tripartite efflux pump in Escherichia coli. ... Bacterial efflux pumps[edit]. Efflux pumps are proteinaceous transporters localized in the cytoplasmic membrane of all kinds of ... Bacterial efflux transporters are classified into five major superfamilies, based on their amino acid sequence and the energy ... Various natural products have been shown to inhibit bacterial efflux pumps including the carotenoids capsanthin and capsorubin, ...
The periplasm is a concentrated gel-like matrix in the space between the inner cytoplasmic membrane and the bacterial outer ... The Bacterial Cell Wall. Berlin: Springer. ISBN 3-540-42608-6. Gupta, R.S. (1998) Protein phylogenies and signature sequences: ... between these membranes. The presence of both inner and outer cell membranes forms and define the periplasmic space or ... all archetypical gram-negative bacteria are bounded by a cytoplasmic membrane as well as an outer cell membrane; they contain ...
"Rickettsial Outer-Membrane Protein B (rOmpB) Mediates Bacterial Invasion through Ku70 in an Actin, c-Cbl, Clathrin and Caveolin ... This species of Rickettsia uses an abundant cell surface protein called OmpB to attach to a host cell membrane protein called ... CDC42, protein tyrosine kinase, phosphoinositide 3-kinase, and Src-family kinases then activate Arp2/3. This causes the ... This causes the host cell membrane to be deformed outward and then it invaginates into the adjacent cell. The bacteria are then ...
... the interaction with the outer bacterial membrane described above is the most dominant and most studied. Lactoferrin not only ... The fraction of protein extracted from milk, contains 3.3% RNA, but, the protein preferably binds to double-stranded DNA rather ... Occurrence of iron-containing red protein in bovine milk was reported as early as in 1939; however, the protein could not be ... optical absorption spectra and presence of two iron atoms per protein molecule. The protein was extracted from milk, contained ...
Bacterial effector protein. *Bacterial outer membrane vesicles. *Host-pathogen interface. *Membrane vesicle trafficking ... the formation of bacterial outer membrane vesicles.[26] Portions of the outer membrane pinch off, forming nano-scale spherical ... complex of pore forming secretin proteins. In addition to the secretin protein, 10-15 other inner and outer membrane proteins ... HlyD recruits TolC to the inner membrane and HlyA is excreted outside of the outer membrane via a long-tunnel protein channel. ...
... as well as an outer membrane auxiliary protein (OMA; TC #3.C.5). Each Gram-positive bacterial PST system functions in ... auxiliary proteins that allow passage across just the cytoplasmic membrane or both membranes of the Gram-negative bacterial ... The protein members of the PST family are generally of 400-500 amino acyl residues in length and traverse the membrane as ... The ANK protein has 12 membrane-spanning helices with a central channel permitting the passage of PPi. Mutations occur at ...
"Characterization of the leptospiral outer membrane and description of three novel leptospiral membrane proteins". Infection and ... NCBI Taxonomy Type strain of Leptospira kirschneri at BacDive - the Bacterial Diversity Metadatabase. ...
The L-ring of the bacterial flagellum is the ring in the lipid outer cell membrane through which the axial filament (rod, hook ... Jones CJ, Homma M, Macnab RM (July 1989). "L-, P-, and M-ring proteins of the flagellar basal body of Salmonella typhimurium: ... gene sequences and deduced protein sequences". J Bacteriol. 171 (7): 3890-3900. PMC 210140 . ...
Outer membrane auxiliary proteins (polysaccharide transporter) - α-helical transmembrane proteins from the outer bacterial ... Outer membrane protein OpcA family (n=10,S=12) that includes outer membrane protease OmpT and adhesin/invasin OpcA protein ... Outer membrane efflux proteins, also known as trimeric outer membrane factors (n=12,S=18) including TolC and multidrug ... Membrane Proteins of known 3D Structure *^ Elofsson, A.; Heijne, G. V. (2007). "Membrane Protein Structure: Prediction versus ...
A protein kinase drifting around on the outer chloroplast membrane can use ATP to add a phosphate group to the Toc34 protein, ... Because it is similar to bacterial amino acid transporters and the mitochondrial import protein Tim17[38] (translocase on the i ... it is known that for about every five Toc75 proteins in the outer chloroplast membrane, there are two Tic20 I proteins (the ... which anchors the protein to the outer chloroplast membrane.[48]. Toc159 probably works a lot like Toc34, recognizing proteins ...
This protein is involved in the pathway lipooligosaccharide biosynthesis, which is part of Bacterial outer membrane biogenesis. ... Cell outer membrane, Membrane. ,p>This section provides information on the disease(s) and phenotype(s) associated with a ... "Characterization of the protein content of a meningococcal outer membrane vesicle vaccine by polyacrylamide gel electrophoresis ... "The Neisseria lipooligosaccharide-specific alpha-2,3-sialyltransferase is a surface-exposed outer membrane protein.". Shell D.M ...
  • In this study, we evaluated the immunologic effects of a combinational vaccination approach using C. trachomatis mouse pneumonitis (MoPn) major outer membrane protein (MOMP) DNA priming followed by boosting with immune-stimulating complexes (ISCOM) of MOMP protein (MOMP ISCOM) for protection of BALB/c mice against MoPn lung infection. (asm.org)
  • We previously reported that C. trachomatis major outer membrane protein (MOMP) DNA immunization induced partial protection against C. trachomatis mouse pneumonitis (MoPn) lung infection, which was associated with Th1 cellular immune responses, variable and low serum antibody responses, and absent immunoglobulin A (IgA) antibody responses ( 23 , 24 ). (asm.org)
  • Immunization with HIV-1 envelope ( env ) DNA followed by env DNA plus HIV Env protein induced high titers of neutralizing antibody and completely protected monkeys from infection after intravenous challenge with a chimeric HIV strain ( 10 ). (asm.org)
  • In the current study, we immunized BALB/c mice with MOMP DNA followed by boosting with MOMP immune-stimulating complex (ISCOM) protein and characterized the resulting immune responses and protective efficacy against C. trachomatis MoPn lung challenge infection. (asm.org)
  • Similar results were observed when mice of different genetic backgrounds (CBA, BALB/c, and C57BL/6) were primed with plasmid DNA encoding a sequence derived from the Plasmodium falciparum antigen Pf155/RESA and boosted with the recombinant malarial protein ( 4 ). (asm.org)
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