Peptides, Cyclic: Peptides whose amino and carboxy ends are linked together with a peptide bond forming a circular chain. Some of them are ANTI-INFECTIVE AGENTS. Some of them are biosynthesized non-ribosomally (PEPTIDE BIOSYNTHESIS, NON-RIBOSOMAL).Oligopeptides: Peptides composed of between two and twelve amino acids.Peptides: 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.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.Peptide Library: A collection of cloned peptides, or chemically synthesized peptides, frequently consisting of all possible combinations of amino acids making up an n-amino acid peptide.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.Tyrocidine: An antibiotic mixture produced by Bacillus brevis which may be separated into three components, tyrocidines A, B, and C. It is the major constituent (40-60 per cent) of tyrothricin, gramicidin accounting for the remaining 10-20 per cent active material. It is a topical antimicrobial agent, that is very toxic parenterally.Momordica: A plant genus of the family CUCURBITACEAE. It is a source of momordin.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Cyclotides: A continuous circle of peptide bonds, typically of 2-3 dozen AMINO ACIDS, so there is no free N- or C-terminus. They are further characterized by six conserved CYSTEINE residues that form CYSTINE KNOT MOTIFS.Cyclization: Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Structure-Activity Relationship: 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.Dianthus: A plant genus of the family CARYOPHYLLACEAE. Members contain dianthins, which are ribosome inactivating proteins.Chalones: Peptides that inhibit mitosis (ANTIMITOTICS). During the 1960's the term referred to crude extracts that inhibited cell proliferation; the activity was later attributed to PYROGLUTAMATE type oligopeptides.Glycylglycine: The simplest of all peptides. It functions as a gamma-glutamyl acceptor.Dipeptides: Peptides composed of two amino acid units.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.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).Oldenlandia: A plant genus of the family RUBIACEAE. Some species are used as an ingredient in Chinese and African traditional medicines. Members contain kalata B1, a macrocyclic peptide.Cystine-Knot Miniproteins: A structurally-related family of small proteins that form a stable tertiary fold pattern which is supported by a series of disulfide bonds. The arrangement of disulfide bonds between the CYSTEINE moieties results in a knotted structure which is unique to this family of proteins.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.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.Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Aminopeptidases: A subclass of EXOPEPTIDASES that act on the free N terminus end of a polypeptide liberating a single amino acid residue. EC 3.4.11.Enviomycin: Cyclic basic peptide related to VIOMYCIN. It is isolated from an induced mutant of Streptomyces griseoverticillatus var. tuberacticus and acts as an antitubercular agent with less ototoxicity than tuberactinomycin.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Combinatorial Chemistry Techniques: A technology, in which sets of reactions for solution or solid-phase synthesis, is used to create molecular libraries for analysis of compounds on a large scale.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Kinetics: The rate dynamics in chemical or physical systems.Antimicrobial Cationic Peptides: Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.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.Depsipeptides: Compounds consisting of chains of AMINO ACIDS alternating with CARBOXYLIC ACIDS via ester and amide linkages. They are commonly cyclized.Peptide Biosynthesis, Nucleic Acid-Independent: The enzymatic synthesis of PEPTIDES without an RNA template by processes that do not use the ribosomal apparatus (RIBOSOMES).Spectrometry, Mass, Fast Atom Bombardment: A mass spectrometric technique that is used for the analysis of a wide range of biomolecules, such as glycoalkaloids, glycoproteins, polysaccharides, and peptides. Positive and negative fast atom bombardment spectra are recorded on a mass spectrometer fitted with an atom gun with xenon as the customary beam. The mass spectra obtained contain molecular weight recognition as well as sequence information.Epitopes: Sites on an antigen that interact with specific antibodies.Microcystins: Cyclic heptapeptides found in MICROCYSTIS and other CYANOBACTERIA. Hepatotoxic and carcinogenic effects have been noted. They are sometimes called cyanotoxins, which should not be confused with chemicals containing a cyano group (CN) which are toxic.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Peptide Synthases: Ligases that catalyze the joining of adjacent AMINO ACIDS by the formation of carbon-nitrogen bonds between their carboxylic acid groups and amine groups.Saponaria: A plant species of the family CARYOPHYLLACEAE. It is a source of SAPONINS. The common name "Soapwort" is also used with VACCARIA. The common name of "Bouncing Bet" is occasionally used with VIOLA.Cephalexin: A semisynthetic cephalosporin antibiotic with antimicrobial activity similar to that of CEPHALORIDINE or CEPHALOTHIN, but somewhat less potent. It is effective against both gram-positive and gram-negative organisms.Molecular Mimicry: The structure of one molecule that imitates or simulates the structure of a different molecule.Bacterial Proteins: Proteins found in any species of bacterium.Annona: A plant genus of the family ANNONACEAE. It has edible fruit and seeds which contain acetogenins and benzoquinazoline and other alkaloids.Endopeptidases: A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.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.Nanotubes, Peptide: NANOTUBES formed from cyclic peptides (PEPTIDES, CYCLIC). Alternating D and L linkages create planar rings that self assemble by stacking into nanotubes. They can form pores through CELL MEMBRANE causing damage to cells.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Recombinant Proteins: Proteins prepared by recombinant DNA technology.Antibodies, Catalytic: Antibodies that can catalyze a wide variety of chemical reactions. They are characterized by high substrate specificity and share many mechanistic features with enzymes.Peptide Hydrolases: Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.Circular Dichroism: 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)Peptide Mapping: Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.Gramicidin: A group of peptide antibiotics from BACILLUS brevis. Gramicidin C or S is a cyclic, ten-amino acid polypeptide and gramicidins A, B, D are linear. Gramicidin is one of the two principal components of TYROTHRICIN.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Cyanobacteria: A phylum of oxygenic photosynthetic bacteria comprised of unicellular to multicellular bacteria possessing CHLOROPHYLL a and carrying out oxygenic PHOTOSYNTHESIS. Cyanobacteria are the only known organisms capable of fixing both CARBON DIOXIDE (in the presence of light) and NITROGEN. Cell morphology can include nitrogen-fixing heterocysts and/or resting cells called akinetes. Formerly called blue-green algae, cyanobacteria were traditionally treated as ALGAE.Defensins: Family of antimicrobial peptides that have been identified in humans, animals, and plants. They are thought to play a role in host defenses against infections, inflammation, wound repair, and acquired immunity.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Leucyl Aminopeptidase: A zinc containing enzyme of the hydrolase class that catalyzes the removal of the N-terminal amino acid from most L-peptides, particularly those with N-terminal leucine residues but not those with N-terminal lysine or arginine residues. This occurs in tissue cell cytosol, with high activity in the duodenum, liver, and kidney. The activity of this enzyme is commonly assayed using a leucine arylamide chromogenic substrate such as leucyl beta-naphthylamide.Lactococcus lactis: A non-pathogenic species of LACTOCOCCUS found in DAIRY PRODUCTS and responsible for the souring of MILK and the production of LACTIC ACID.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.Capreomycin: Cyclic peptide antibiotic similar to VIOMYCIN. It is produced by Streptomyces capreolus.Microcystis: A form-genus of CYANOBACTERIA in the order Chroococcales. Many species are planktonic and possess gas vacuoles.Hydrophobic and Hydrophilic Interactions: The thermodynamic interaction between a substance and WATER.Protease Inhibitors: Compounds which inhibit or antagonize biosynthesis or actions of proteases (ENDOPEPTIDASES).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.Proline: A non-essential amino acid that is synthesized from GLUTAMIC ACID. It is an essential component of COLLAGEN and is important for proper functioning of joints and tendons.Natriuretic Peptide, Brain: A PEPTIDE that is secreted by the BRAIN and the HEART ATRIA, stored mainly in cardiac ventricular MYOCARDIUM. It can cause NATRIURESIS; DIURESIS; VASODILATION; and inhibits secretion of RENIN and ALDOSTERONE. It improves heart function. It contains 32 AMINO ACIDS.Hydrogen-Ion Concentration: 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)Molecular Weight: The sum of the weight of all the atoms in a molecule.Drug Design: The molecular designing of drugs for specific purposes (such as DNA-binding, enzyme inhibition, anti-cancer efficacy, etc.) based on knowledge of molecular properties such as activity of functional groups, molecular geometry, and electronic structure, and also on information cataloged on analogous molecules. Drug design is generally computer-assisted molecular modeling and does not include pharmacokinetics, dosage analysis, or drug administration analysis.Nuclear Magnetic Resonance, Biomolecular: NMR spectroscopy on small- to medium-size biological macromolecules. This is often used for structural investigation of proteins and nucleic acids, and often involves more than one isotope.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.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.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Enzyme-Linked Immunosorbent Assay: An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization: A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis.Disulfides: Chemical groups containing the covalent disulfide bonds -S-S-. The sulfur atoms can be bound to inorganic or organic moieties.Caseins: A mixture of related phosphoproteins occurring in milk and cheese. The group is characterized as one of the most nutritive milk proteins, containing all of the common amino acids and rich in the essential ones.Alanine: A non-essential amino acid that occurs in high levels in its free state in plasma. It is produced from pyruvate by transamination. It is involved in sugar and acid metabolism, increases IMMUNITY, and provides energy for muscle tissue, BRAIN, and the CENTRAL NERVOUS SYSTEM.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Dipeptidyl-Peptidases and Tripeptidyl-Peptidases: A subclass of exopeptidases that includes enzymes which cleave either two or three AMINO ACIDS from the end of a peptide chain.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Lysine: An essential amino acid. It is often added to animal feed.Vasoactive Intestinal Peptide: A highly basic, 28 amino acid neuropeptide released from intestinal mucosa. It has a wide range of biological actions affecting the cardiovascular, gastrointestinal, and respiratory systems and is neuroprotective. It binds special receptors (RECEPTORS, VASOACTIVE INTESTINAL PEPTIDE).Glycine: A non-essential amino acid. It is found primarily in gelatin and silk fibroin and used therapeutically as a nutrient. It is also a fast inhibitory neurotransmitter.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Spectrometry, Mass, Electrospray Ionization: A mass spectrometry technique used for analysis of nonvolatile compounds such as proteins and macromolecules. The technique involves preparing electrically charged droplets from analyte molecules dissolved in solvent. The electrically charged droplets enter a vacuum chamber where the solvent is evaporated. Evaporation of solvent reduces the droplet size, thereby increasing the coulombic repulsion within the droplet. As the charged droplets get smaller, the excess charge within them causes them to disintegrate and release analyte molecules. The volatilized analyte molecules are then analyzed by mass spectrometry.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.Calcitonin Gene-Related Peptide: Calcitonin gene-related peptide. A 37-amino acid peptide derived from the calcitonin gene. It occurs as a result of alternative processing of mRNA from the calcitonin gene. The neuropeptide is widely distributed in neural tissue of the brain, gut, perivascular nerves, and other tissue. The peptide produces multiple biological effects and has both circulatory and neurotransmitter modes of action. In particular, it is a potent endogenous vasodilator.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Intestinal Absorption: Uptake of substances through the lining of the INTESTINES.Cell-Penetrating Peptides: Peptides that have the ability to enter cells by crossing the plasma membrane directly, or through uptake by the endocytotic pathway.Mycotoxins: Toxic compounds produced by FUNGI.Molecular Conformation: The characteristic three-dimensional shape of a molecule.Sequence Analysis, Protein: A process that includes the determination of AMINO ACID SEQUENCE of a protein (or peptide, oligopeptide or peptide fragment) and the information analysis of the sequence.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.Lipopeptides: Compounds consisting of a short peptide chain conjugated with an acyl chain.Peptide Biosynthesis: The production of PEPTIDES or PROTEINS by the constituents of a living organism. The biosynthesis of proteins on RIBOSOMES following an RNA template is termed translation (TRANSLATION, GENETIC). There are other, non-ribosomal peptide biosynthesis (PEPTIDE BIOSYNTHESIS, NUCLEIC ACID-INDEPENDENT) mechanisms carried out by PEPTIDE SYNTHASES and PEPTIDYLTRANSFERASES. Further modifications of peptide chains yield functional peptide and protein molecules.Streptomyces: A genus of bacteria that form a nonfragmented aerial mycelium. Many species have been identified with some being pathogenic. This genus is responsible for producing a majority of the ANTI-BACTERIAL AGENTS of practical value.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.Peptide YY: A 36-amino acid peptide produced by the L cells of the distal small intestine and colon. Peptide YY inhibits gastric and pancreatic secretion.Metalloendopeptidases: ENDOPEPTIDASES which use a metal such as ZINC in the catalytic mechanism.Serine Endopeptidases: Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.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.Peptide Nucleic Acids: DNA analogs containing neutral amide backbone linkages composed of aminoethyl glycine units instead of the usual phosphodiester linkage of deoxyribose groups. Peptide nucleic acids have high biological stability and higher affinity for complementary DNA or RNA sequences than analogous DNA oligomers.Amino Acid Motifs: Commonly observed structural components of proteins formed by simple combinations of adjacent secondary structures. A commonly observed structure may be composed of a CONSERVED SEQUENCE which can be represented by a CONSENSUS SEQUENCE.Hemolysis: The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.Inhibitory Concentration 50: The concentration of a compound needed to reduce population growth of organisms, including eukaryotic cells, by 50% in vitro. Though often expressed to denote in vitro antibacterial activity, it is also used as a benchmark for cytotoxicity to eukaryotic cells in culture.Gram-Positive Bacteria: Bacteria which retain the crystal violet stain when treated by Gram's method.Natriuretic Peptide, C-Type: A PEPTIDE of 22 amino acids, derived mainly from cells of VASCULAR ENDOTHELIUM. It is also found in the BRAIN, major endocrine glands, and other tissues. It shares structural homology with ATRIAL NATRIURETIC FACTOR. It has vasorelaxant activity thus is important in the regulation of vascular tone and blood flow. Several high molecular weight forms containing the 22 amino acids have been identified.Biological Transport, Active: The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.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.Tandem Mass Spectrometry: A mass spectrometry technique using two (MS/MS) or more mass analyzers. With two in tandem, the precursor ions are mass-selected by a first mass analyzer, and focused into a collision region where they are then fragmented into product ions which are then characterized by a second mass analyzer. A variety of techniques are used to separate the compounds, ionize them, and introduce them to the first mass analyzer. For example, for in GC-MS/MS, GAS CHROMATOGRAPHY-MASS SPECTROMETRY is involved in separating relatively small compounds by GAS CHROMATOGRAPHY prior to injecting them into an ionization chamber for the mass selection.Natriuretic Peptides: Peptides that regulate the WATER-ELECTROLYTE BALANCE in the body, also known as natriuretic peptide hormones. Several have been sequenced (ATRIAL NATRIURETIC FACTOR; BRAIN NATRIURETIC PEPTIDE; C-TYPE NATRIURETIC PEPTIDE).Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Gastrin-Releasing Peptide: Neuropeptide and gut hormone that helps regulate GASTRIC ACID secretion and motor function. Once released from nerves in the antrum of the STOMACH, the neuropeptide stimulates release of GASTRIN from the GASTRIN-SECRETING CELLS.Viral Proteins: Proteins found in any species of virus.Integrin alphaVbeta3: An integrin that binds to a variety of plasma and extracellular matrix proteins containing the conserved RGD amino acid sequence and modulates cell adhesion. Integrin alphavbeta3 is highly expressed in OSTEOCLASTS where it may play role in BONE RESORPTION. It is also abundant in vascular smooth muscle and endothelial cells, and in some tumor cells, where it is involved in angiogenesis and cell migration. Although often referred to as the vitronectin receptor there is more than one receptor for vitronectin (RECEPTORS, VITRONECTIN).Protons: Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Receptors, Formyl Peptide: A family of G-protein-coupled receptors that was originally identified by its ability to bind N-formyl peptides such as N-FORMYLMETHIONINE LEUCYL-PHENYLALANINE. Since N-formyl peptides are found in MITOCHONDRIA and BACTERIA, this class of receptors is believed to play a role in mediating cellular responses to cellular damage and bacterial invasion. However, non-formylated peptide ligands have also been found for this receptor class.Ligands: A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)Peptide PHI: A 27-amino acid peptide with histidine at the N-terminal and isoleucine amide at the C-terminal. The exact amino acid composition of the peptide is species dependent. The peptide is secreted in the intestine, but is found in the nervous system, many organs, and in the majority of peripheral tissues. It has a wide range of biological actions, affecting the cardiovascular, gastrointestinal, respiratory, and central nervous systems.Solutions: The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)Fungi: A kingdom of eukaryotic, heterotrophic organisms that live parasitically as saprobes, including MUSHROOMS; YEASTS; smuts, molds, etc. They reproduce either sexually or asexually, and have life cycles that range from simple to complex. Filamentous fungi, commonly known as molds, refer to those that grow as multicellular colonies.Receptors, Peptide: Cell surface receptors that bind peptide messengers with high affinity and regulate intracellular signals which influence the behavior of cells.Multigene Family: A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)Atrial Natriuretic Factor: A potent natriuretic and vasodilatory peptide or mixture of different-sized low molecular weight PEPTIDES derived from a common precursor and secreted mainly by the HEART ATRIUM. All these peptides share a sequence of about 20 AMINO ACIDS.Receptors, Vitronectin: Receptors such as INTEGRIN ALPHAVBETA3 that bind VITRONECTIN with high affinity and play a role in cell migration. They also bind FIBRINOGEN; VON WILLEBRAND FACTOR; osteopontin; and THROMBOSPONDINS.Microbial Sensitivity Tests: Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).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.Integrins: A family of transmembrane glycoproteins (MEMBRANE GLYCOPROTEINS) consisting of noncovalent heterodimers. They interact with a wide variety of ligands including EXTRACELLULAR MATRIX PROTEINS; COMPLEMENT, and other cells, while their intracellular domains interact with the CYTOSKELETON. The integrins consist of at least three identified families: the cytoadhesin receptors(RECEPTORS, CYTOADHESIN), the leukocyte adhesion receptors (RECEPTORS, LEUKOCYTE ADHESION), and the VERY LATE ANTIGEN RECEPTORS. Each family contains a common beta-subunit (INTEGRIN BETA CHAINS) combined with one or more distinct alpha-subunits (INTEGRIN ALPHA CHAINS). These receptors participate in cell-matrix and cell-cell adhesion in many physiologically important processes, including embryological development; HEMOSTASIS; THROMBOSIS; WOUND HEALING; immune and nonimmune defense mechanisms; and oncogenic transformation.Biological Products: Complex pharmaceutical substances, preparations, or matter derived from organisms usually obtained by biological methods or assay.CHO Cells: CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.Ascomycota: A phylum of fungi which have cross-walls or septa in the mycelium. The perfect state is characterized by the formation of a saclike cell (ascus) containing ascospores. Most pathogenic fungi with a known perfect state belong to this phylum.Antigens, Viral: Substances elaborated by viruses that have antigenic activity.Cell Line, Tumor: A cell line derived from cultured tumor cells.Antibody Specificity: The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.Protein PrecursorsHigh-Throughput Screening Assays: Rapid methods of measuring the effects of an agent in a biological or chemical assay. The assay usually involves some form of automation or a way to conduct multiple assays at the same time using sample arrays.Models, Chemical: Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Cell Adhesion: Adherence of cells to surfaces or to other cells.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Bacteriophages: Viruses whose hosts are bacterial cells.Cell Membrane Permeability: A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.Trypsin: A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.Antibodies, Viral: Immunoglobulins produced in response to VIRAL ANTIGENS.Water: A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Mice, Inbred BALB CBacillus: A genus of BACILLACEAE that are spore-forming, rod-shaped cells. Most species are saprophytic soil forms with only a few species being pathogenic.Opioid Peptides: The endogenous peptides with opiate-like activity. The three major classes currently recognized are the ENKEPHALINS, the DYNORPHINS, and the ENDORPHINS. Each of these families derives from different precursors, proenkephalin, prodynorphin, and PRO-OPIOMELANOCORTIN, respectively. There are also at least three classes of OPIOID RECEPTORS, but the peptide families do not map to the receptors in a simple way.Intracellular Signaling Peptides and Proteins: Proteins and peptides that are involved in SIGNAL TRANSDUCTION within the cell. Included here are peptides and proteins that regulate the activity of TRANSCRIPTION FACTORS and cellular processes in response to signals from CELL SURFACE RECEPTORS. Intracellular signaling peptide and proteins may be part of an enzymatic signaling cascade or act through binding to and modifying the action of other signaling factors.Peptide Hormones: Hormones synthesized from amino acids. They are distinguished from INTERCELLULAR SIGNALING PEPTIDES AND PROTEINS in that their actions are systemic.Time Factors: Elements of limited time intervals, contributing to particular results or situations.
  • An Investigation of Oligopeptides Linking Domains in Protein Tertiary Structures and Possible Candidates for General Gene Fusion" (PDF). (wikipedia.org)
  • neurophysin is a large peptide fragment of the giant precursor protein molecule from which oxytocin is derived by enzymatic cleavage. (hmdb.ca)
  • PROBLEM TO BE SOLVED: To provide an oligopeptide (tag) for purifying an objective protein and a polymer substrate for metal ion affinity chromatography. (ideaconnection.com)
  • The fusion protein has a protein in which the oligopeptide is fused with the amino terminal or carboxy terminal of an objective protein molecule. (ideaconnection.com)
  • But only now emerging is the recognition that peptides can Self-assemble into a wide variety of non-protein-like structures, including fibrils, fibres, tubules, sheets and monolayers. (springer.com)
  • Human creativity has led to peptides being important tools for understanding protein structure and function. (newworldencyclopedia.org)
  • Peptides also allow antibodies to be generated without the need to purify the protein of interest, by making antigenic peptides of sections of the protein. (newworldencyclopedia.org)
  • For each step in the biological synthesis of a peptide or protein there is a specific enzyme or enzyme complex that catalyzes each reaction in an ordered fashion along the biosynthetic route. (thefreedictionary.com)
  • Endotoxin-neutralizing protein, a recombinant peptide that is derived from Limulus antilipopolysaccharide factor and targets lipid A, could block the effects of lipopolysaccharide on protein tyrosine phosphorylation, actin organization, and movement of 14C-bovine serum albumin across bovine pulmonary artery endothelial cell monolayers. (igem.org)
  • However, previous investigations with cysteine- and non-cysteine- containing peptides derived from TALF, a protein highly homologous with LALF, showed little difference in LPS binding activity (23). (igem.org)
  • Compounds tiny еnough to bee synthesized fгom the constituent amiino acids аre, ƅy meeting, termed peptides in рlace of protein. (blogspot.com)
  • Agouti-related protein (AgRP) is a 4-kDa cystine-knot peptide of human origin with four disulfide bonds and four solvent-exposed loops. (hindawi.com)
  • Previously, we used a truncated form of the Agouti-related protein (AgRP*), a 4-kDa cystine-knot peptide with four disulfide bonds and four solvent-exposed loops, as a molecular scaffold for directed evolution. (hindawi.com)
  • In the thrombo-erythrocytes of the invention, preferably, the N-terminal Arg of the R-G-D sequence should be spaced within 9-50 Angstroms, more preferably 10-40 Angstroms, and most preferably 11-25 Angstroms, from the erythrocyte protein to which the RGD peptide is conjugated. (freepatentsonline.com)
  • 1981, "Chemically synthesized peptides predicted from the nucleotide sequence of the hepatitis B virus genome elicit antibodies reactive with the native envelope protein of Dane particles," Proc. (freepatentsonline.com)
  • Further more, some protein and peptide-based carriers are nearly invisible to the immune system and are expected to cause minimal or no side effects 8 . (ijpsr.com)
  • Due to these considerable advantages over other synthetic approaches, CLRP techniques have been successfully exploited to construct novel polymer-protein/peptide bioconjugates with a high level of structural control and varied interesting, somehow unexpected, features. (rsc.org)
  • The attachment of polyethylene glycol (PEG) to protein or peptide therapeutics, termed PEGylation, is an example of a highly successful strategy that gives rise to several benefits including increased bioavailability and plasma half-lives, decreased immunogenicity, reduced proteolysis and enhanced solubility and stability. (rsc.org)
  • After identification of a protective epitope, it is possi-ble to incorporate the corresponding peptide sequence through genetic fusion into a carrier protein, such as HBsAg, hepatitis B core antigen, and β-galactosidase (Francis and Larche, 2005). (brainkart.com)
  • The peptide-encoding DNA sequence is synthesized and inserted into the carrier protein gene. (brainkart.com)
  • 2 Recently, a cyclic ß-tetrapeptide was synthesized with biological activity similar to somatostatine, an important endogenous neurotransmitter and inhibitor of hormone secretion. (sigmaaldrich.com)
  • Tentoxin (cyclo(N-methyl-L-alanyl-L-leucyl-N-methyl-trans-dehydrophenyl-alanyl-glycyl)) is a natural cyclic tetrapeptide produced by phytopathogenic fungi from genus Alternaria . (chempep.com)
  • as well as a Mega-Rich Anti-Aging Sleeping Mask fueled by Proprietary FirmaCELL-4 which contains four different molecular size peptides: Syn-Coll, Palmitoyl Tetrapeptide-7, Palmitoyl Oligopeptide and neuropeptide Argireline to help firm, tone, smooth and clarify the look of skin, reducing the appearance of fine lines and the severity of deep wrinkles for younger looking skin. (thefreedictionary.com)
  • A particular blend of peptides (palmitoyl oligopeptide and palmitoyl tetrapeptide) works by helping tighten the delicate tissue. (thefreedictionary.com)
  • Becker JA, Wallace A, Garzon A, Ingallinella P, Bianchi E, Cortese R, Simonin F, Kieffer BL, Pessi A (1999) Ligands for kappa-opioid and ORL1 receptors identified from a conformationally constrained peptide combinatorial library. (springer.com)
  • Bigoni R, Rizzi A, Rizzi D, Becker JA, Kieffer BL, Simonin F, Regoli D, Calo' G (2000) In vitro pharmacological profile of peptide III-BTD: a novel ligand for nociceptin/orphanin FQ and opioid receptors. (springer.com)
  • Dynamic Peptides as Biomimetic Carbohydrate Receptors. (docme.ru)
  • A more versatile approach towards the recognition of carbohydrates in water is based on the coordination of carbohydrates and boronic acids, including peptides functionalized with boronic acids, but it should be emphasized that these innovative materials are covalent carbohydrate binders rather than noncovalent biomimetic receptors. (docme.ru)
  • We explore a dynamic combinatorial library (DCL) of cyclic peptides to select receptors that are assembled from tripeptides under thermodynamic equilibrium. (docme.ru)
  • Although carbohydrates and peptides have been used as building blocks in dynamic combinatorial chemistry, there are no reports on the selection of carbohydrate receptors by this methodology. (docme.ru)
  • For all scientific studies except IVM, 8 to 10 week old female mice were inoculated subcutaneously with 1 106 CT 26 tumor cells harvested from exponentially rising cultures and utilized for custom peptide value experimentation f 7 to 8 days immediately after inoculation, when tumors had reached a diameter of 6 to 7 mm. (statsignaling.com)
  • Its mechanism of action is still up for debate, and it probably acts via more than one, but it does indeed seem to enhance uptake of peptides. (sciencemag.org)
  • We identified a genetic context encoding a transcriptional regulator of the Rgg family and a small hydrophobic peptide (SHP) in nearly all streptococci and suggested that it may be involved in a new quorumsensing mechanism, with SHP playing the role of a pheromone. (uclouvain.be)
  • Our findings demonstrate that the shp/rgg1358 locus encodes two components of a novel quorum-sensing mechanism involving a transcriptional regulator of the Rgg family and a SHP pheromone that is detected and reimported into the cell by the Ami oligopeptide transporter. (uclouvain.be)
  • The oligopeptide low-molecular-weight chromium-binding substance (LMWCr) may function as part of a novel insulin-signaling autoamplification mechanism. (thefreedictionary.com)
  • waste', based оn , 'to digest') аre quick restaurants of amino acid monomers rеlated Ƅy peptide (amide) securities. (blogspot.com)
  • In case of cyclosporin, we have an additional reason for unusual molecular behavior: absence of several amide protons, which in typical peptides can form hydrogen bonds and thus stabilize the structure. (kpfu.ru)
  • Tuftsin (L-threonyl-L-lysyl-L-prolyl-L-arginine) is a peptide related primarily to the immune system function. (chempep.com)
  • The object of the present invention is to provide an oligopeptide having hair growth promoting activity. (google.es)
  • This is consistent with the peptide acting as a chemokine inhibitor up-steam of TNF-α productsion and anti-inflammatory in vivo. (wikipedia.org)
  • The cyclic peptide NR58-3.14.3 was shown to be a powerful anti-inflammatory agent in vivo inhibiting inflammation in a number of disease models such as atherosclerosis, ischemia, lung disease, surgical adhesions, endometriosis and pulmonary graft-versus-host disease. (wikipedia.org)
  • The CL uptake, vivo of these four peptides in vivo was similar to the extrapolated values based on the carrier-mediated transport activity previously assessed in vitro in isolated rat hepatocytes. (aspetjournals.org)
  • Peptides identified using this technique have been successfully used for specific site drug delivery and in vivo imaging ( Deutscher, 2010 ). (frontiersin.org)
  • Peptide microarrays that display overlapping peptide scans through antigens from infectious organisms or tumor associated antigens for antibody or serum profiling. (jpt.com)
  • Leupeptins - A group of acylated oligopeptides produced by Actinomycetes that function as protease inhibitors. (wikipedia.org)
  • Such as inhibitors can be used, for example, as a means of increasing cyclic AMP in neurons and thus treating neurological problems, such as long term memory loss, if not preventing such maladies entirely. (freepatentsonline.com)
  • And agents including these: -- Complement factor inhibition and serotonin modifiers -- Anti-integrin oligopeptide treatment -- Oligonucleotides and siRNA therapy -- Angiotensin receptor blockers and converting enzyme inhibitors -- Regenerative medicine, neural stem cells, cellular and gene therapies. (thefreedictionary.com)
  • additionally, tҺese small-peptide antioxidants are consideredd to penetrate cells іn an energy-separate ɑnd neo-saturable mannerr with no neеd for peptide transporter. (blogspot.com)
  • fuгthermore, theese lіttle-peptide antioxidants аre thouցht to penetrate clls wirhin an energy-impartial аnd low-saturable աay with no requirement fօr peptide transporter. (blogspot.com)
  • We investigated for the first time the oligopeptide diversity within a natural Microcystis population by analyzing single colonies directly with matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The results demonstrate a high diversity of known cyanobacterial peptides such as microcystins, anabaenopeptins, microginins, aeruginosins, and cyanopeptolins, but also many unknown substances in the Microcystis colonies. (pubmedcentralcanada.ca)
  • Peptide toxin production was screened by matrix assisted laser desorption/ionization time of flight mass spectrometry. (mdpi.com)
  • Although mass spectrometry analysis did not reveal the production of microcystins or other known toxic peptides, a positive result for the presence of mcyE gene was found in one Leptolyngbya strain and one Oscillatoria strain. (mdpi.com)
  • Peptide sets and pools, as well as assay standardization kits are available with stable isotope labeled or unlabeled proteotypic peptides for mass-spectrometry based proteomics such as MRM assays. (jpt.com)
  • Simply swelling such an unprotected peptide-[thioester]-resin in aqueous buffer results in a chemoselective ligation reaction and concomitant cleavage of the peptide from the support. (nih.gov)
  • Reaction of peptide aldehydes with serine proteases. (meta.org)
  • The results of Table 1 show that the formation of peptides is strongly dependent on the pH of the reaction medium. (sciencemag.org)