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).Molecular Conformation: The characteristic three-dimensional shape of a molecule.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.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)Protein Folding: Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.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.Thermodynamics: A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)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.Deuterium Exchange Measurement: A research technique to measure solvent exposed regions of molecules that is used to provide insight about PROTEIN CONFORMATION.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.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.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.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.Optical Rotatory Dispersion: The method of measuring the dispersion of an optically active molecule to determine the relative magnitude of right- or left-handed components and sometimes structural features of the molecule.Protein Denaturation: Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.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).Kinetics: The rate dynamics in chemical or physical 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)Hydrogen Bonding: A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.Silica Gel: A non-crystalline form of silicon oxide that has absorptive properties. It is commonly used as a desiccating agent and as a stationary phase for CHROMATOGRAPHY. The fully hydrated form of silica gel has distinct properties and is referred to as SILICIC ACID.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.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)Myoglobin: A conjugated protein which is the oxygen-transporting pigment of muscle. It is made up of one globin polypeptide chain and one heme group.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.Molecular Dynamics Simulation: A computer simulation developed to study the motion of molecules over a period of time.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.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.Spectrum Analysis, Raman: Analysis of the intensity of Raman scattering of monochromatic light as a function of frequency of the scattered light.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)Tryptophan: An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.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.Anilino Naphthalenesulfonates: A class of organic compounds which contain an anilino (phenylamino) group linked to a salt or ester of naphthalenesulfonic acid. They are frequently used as fluorescent dyes and sulfhydryl reagents.Protein Structure, Quaternary: The characteristic 3-dimensional shape and arrangement of multimeric proteins (aggregates of more than one polypeptide chain).Spectroscopy, Fourier Transform Infrared: A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Protein Stability: The ability of a protein to retain its structural conformation or its activity when subjected to physical or chemical manipulations.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.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.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)Amino Acid Substitution: The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.Muramidase: A basic enzyme that is present in saliva, tears, egg white, and many animal fluids. It functions as an antibacterial agent. The enzyme catalyzes the hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrin. EC 3.2.1.17.Apoproteins: The protein components of a number of complexes, such as enzymes (APOENZYMES), ferritin (APOFERRITINS), or lipoproteins (APOLIPOPROTEINS).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.Hydrogen: The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.Prions: Small proteinaceous infectious particles which resist inactivation by procedures that modify NUCLEIC ACIDS and contain an abnormal isoform of a cellular protein which is a major and necessary component. The abnormal (scrapie) isoform is PrPSc (PRPSC PROTEINS) and the cellular isoform PrPC (PRPC PROTEINS). The primary amino acid sequence of the two isoforms is identical. Human diseases caused by prions include CREUTZFELDT-JAKOB SYNDROME; GERSTMANN-STRAUSSLER SYNDROME; and INSOMNIA, FATAL FAMILIAL.Guanidine: A strong organic base existing primarily as guanidium ions at physiological pH. It is found in the urine as a normal product of protein metabolism. It is also used in laboratory research as a protein denaturant. (From Martindale, the Extra Pharmacopoeia, 30th ed and Merck Index, 12th ed) It is also used in the treatment of myasthenia and as a fluorescent probe in HPLC.Solvents: Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)Bacteriorhodopsins: Rhodopsins found in the PURPLE MEMBRANE of halophilic archaea such as HALOBACTERIUM HALOBIUM. Bacteriorhodopsins function as an energy transducers, converting light energy into electrochemical energy via PROTON PUMPS.Spectrophotometry, Infrared: Spectrophotometry in the infrared region, usually for the purpose of chemical analysis through measurement of absorption spectra associated with rotational and vibrational energy levels of molecules. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Static Electricity: The accumulation of an electric charge on a objectSpectrophotometry, Ultraviolet: Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Schiff Bases: Condensation products of aromatic amines and aldehydes forming azomethines substituted on the N atom, containing the general formula R-N:CHR. (From Grant & Hackh's Chemical Dictionary, 5th ed)Bacterial Proteins: Proteins found in any species of bacterium.Amyloid: A fibrous protein complex that consists of proteins folded into a specific cross beta-pleated sheet structure. This fibrillar structure has been found as an alternative folding pattern for a variety of functional proteins. Deposits of amyloid in the form of AMYLOID PLAQUES are associated with a variety of degenerative diseases. The amyloid structure has also been found in a number of functional proteins that are unrelated to disease.Biophysics: The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Hydrophobic and Hydrophilic Interactions: The thermodynamic interaction between a substance and WATER.Horses: Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.Deuterium: Deuterium. The stable isotope of hydrogen. It has one neutron and one proton in the nucleus.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Dimerization: The process by which two molecules of the same chemical composition form a condensation product or polymer.Biophysical Phenomena: The physical characteristics and processes of biological systems.PhotochemistryCrystallization: The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Spectrum Analysis: The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)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.Hydrostatic Pressure: The pressure due to the weight of fluid.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Macromolecular Substances: Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Fluorescence Resonance Energy Transfer: A type of FLUORESCENCE SPECTROSCOPY using two FLUORESCENT DYES with overlapping emission and absorption spectra, which is used to indicate proximity of labeled molecules. This technique is useful for studying interactions of molecules and PROTEIN FOLDING.Prion Diseases: A group of genetic, infectious, or sporadic degenerative human and animal nervous system disorders associated with abnormal PRIONS. These diseases are characterized by conversion of the normal prion protein to an abnormal configuration via a post-translational process. In humans, these conditions generally feature DEMENTIA; ATAXIA; and a fatal outcome. Pathologic features include a spongiform encephalopathy without evidence of inflammation. The older literature occasionally refers to these as unconventional SLOW VIRUS DISEASES. (From Proc Natl Acad Sci USA 1998 Nov 10;95(23):13363-83)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).Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.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.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Chymotrypsin: A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Energy Transfer: The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.Enzyme Stability: The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Chemistry, Physical: The study of CHEMICAL PHENOMENA and processes in terms of the underlying PHYSICAL PHENOMENA and processes.Physicochemical Phenomena: The physical phenomena describing the structure and properties of atoms and molecules, and their reaction and interaction processes.Amides: Organic compounds containing the -CO-NH2 radical. Amides are derived from acids by replacement of -OH by -NH2 or from ammonia by the replacement of H by an acyl group. (From Grant & Hackh's Chemical Dictionary, 5th ed)Cysteine: A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.Mutant Proteins: Proteins produced from GENES that have acquired MUTATIONS.Molecular Chaperones: A family of cellular proteins that mediate the correct assembly or disassembly of polypeptides and their associated ligands. Although they take part in the assembly process, molecular chaperones are not components of the final structures.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.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.Point Mutation: A mutation caused by the substitution of one nucleotide for another. This results in the DNA molecule having a change in a single base pair.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.Polymorphism, Single-Stranded Conformational: Variation in a population's DNA sequence that is detected by determining alterations in the conformation of denatured DNA fragments. Denatured DNA fragments are allowed to renature under conditions that prevent the formation of double-stranded DNA and allow secondary structure to form in single stranded fragments. These fragments are then run through polyacrylamide gels to detect variations in the secondary structure that is manifested as an alteration in migration through the gels.Electron Spin Resonance Spectroscopy: A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.Ions: An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.Hemeproteins: Proteins that contain an iron-porphyrin, or heme, prosthetic group resembling that of hemoglobin. (From Lehninger, Principles of Biochemistry, 1982, p480)Adenosine Triphosphate: An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.Microscopy, Atomic Force: A type of scanning probe microscopy in which a probe systematically rides across the surface of a sample being scanned in a raster pattern. The vertical position is recorded as a spring attached to the probe rises and falls in response to peaks and valleys on the surface. These deflections produce a topographic map of the sample.Heme: The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.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.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.Fourier Analysis: Analysis based on the mathematical function first formulated by Jean-Baptiste-Joseph Fourier in 1807. The function, known as the Fourier transform, describes the sinusoidal pattern of any fluctuating pattern in the physical world in terms of its amplitude and its phase. It has broad applications in biomedicine, e.g., analysis of the x-ray crystallography data pivotal in identifying the double helical nature of DNA and in analysis of other molecules, including viruses, and the modified back-projection algorithm universally used in computerized tomography imaging, etc. (From Segen, The Dictionary of Modern Medicine, 1992)Urea: A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.Fluorescent Dyes: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.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.Glycosylation: The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction.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.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)Carbohydrate Conformation: The characteristic 3-dimensional shape of a carbohydrate.Databases, Protein: Databases containing information about PROTEINS such as AMINO ACID SEQUENCE; PROTEIN CONFORMATION; and other properties.Lysine: An essential amino acid. It is often added to animal feed.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.Cell Line: Established cell cultures that have the potential to propagate indefinitely.X-Ray Diffraction: The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)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.Cytochrome c Group: A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)Computational Biology: A field of biology concerned with the development of techniques for the collection and manipulation of biological data, and the use of such data to make biological discoveries or predictions. This field encompasses all computational methods and theories for solving biological problems including manipulation of models and datasets.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Epitopes: Sites on an antigen that interact with specific antibodies.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.Protein Processing, Post-Translational: Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.Aspartic Acid: One of the non-essential amino acids commonly occurring in the L-form. It is found in animals and plants, especially in sugar cane and sugar beets. It may be a neurotransmitter.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Zinc: A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.Catalytic Domain: The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.Molecular Weight: The sum of the weight of all the atoms in a molecule.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Serum Albumin, Bovine: Serum albumin from cows, commonly used in in vitro biological studies. (From Stedman, 25th ed)Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.Crystallography: The branch of science that deals with the geometric description of crystals and their internal arrangement. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Hemoglobins: The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Software: Sequential operating programs and data which instruct the functioning of a digital computer.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Electron Transport: The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Time Factors: Elements of limited time intervals, contributing to particular results or situations.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.Polydeoxyribonucleotides: A group of 13 or more deoxyribonucleotides in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.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.Protein Multimerization: The assembly of the QUATERNARY PROTEIN STRUCTURE of multimeric proteins (MULTIPROTEIN COMPLEXES) from their composite PROTEIN SUBUNITS.Saccharomyces cerevisiae Proteins: Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.Disulfides: Chemical groups containing the covalent disulfide bonds -S-S-. The sulfur atoms can be bound to inorganic or organic moieties.Allosteric Regulation: The modification of the reactivity of ENZYMES by the binding of effectors to sites (ALLOSTERIC SITES) on the enzymes other than the substrate BINDING SITES.Trifluoroethanol: A non-aqueous co-solvent that serves as tool to study protein folding. It is also used in various pharmaceutical, chemical and engineering applications.Scattering, Small Angle: Scattering of a beam of electromagnetic or acoustic RADIATION, or particles, at small angles by particles or cavities whose dimensions are many times as large as the wavelength of the radiation or the de Broglie wavelength of the scattered particles. Also know as low angle scattering. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed) Small angle scattering (SAS) techniques, small angle neutron (SANS), X-ray (SAXS), and light (SALS, or just LS) scattering, are used to characterize objects on a nanoscale.Magnesium: A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.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)Models, Structural: A representation, generally small in scale, to show the structure, construction, or appearance of something. (From Random House Unabridged Dictionary, 2d 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.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.Structural Homology, Protein: The degree of 3-dimensional shape similarity between proteins. It can be an indication of distant AMINO ACID SEQUENCE HOMOLOGY and used for rational DRUG DESIGN.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Lipid Bilayers: Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.Oligodeoxyribonucleotides: A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.Allosteric Site: A site on an enzyme which upon binding of a modulator, causes the enzyme to undergo a conformational change that may alter its catalytic or binding properties.Calorimetry: The measurement of the quantity of heat involved in various processes, such as chemical reactions, changes of state, and formations of solutions, or in the determination of the heat capacities of substances. The fundamental unit of measurement is the joule or the calorie (4.184 joules). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)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.Base Pairing: Pairing of purine and pyrimidine bases by HYDROGEN BONDING in double-stranded DNA or RNA.Isomerism: The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Nucleic Acid Denaturation: Disruption of the secondary structure of nucleic acids by heat, extreme pH or chemical treatment. Double strand DNA is "melted" by dissociation of the non-covalent hydrogen bonds and hydrophobic interactions. Denatured DNA appears to be a single-stranded flexible structure. The effects of denaturation on RNA are similar though less pronounced and largely reversible.Oligopeptides: Peptides composed of between two and twelve amino acids.Micelles: Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.Nucleotides: The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)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.Cross-Linking Reagents: Reagents with two reactive groups, usually at opposite ends of the molecule, that are capable of reacting with and thereby forming bridges between side chains of amino acids in proteins; the locations of naturally reactive areas within proteins can thereby be identified; may also be used for other macromolecules, like glycoproteins, nucleic acids, or other.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.RNA: A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Cryoelectron Microscopy: Electron microscopy involving rapid freezing of the samples. The imaging of frozen-hydrated molecules and organelles permits the best possible resolution closest to the living state, free of chemical fixatives or stains.Mutagenesis: Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.Histidine: An essential amino acid that is required for the production of HISTAMINE.Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.Chemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.Protein Subunits: Single chains of amino acids that are the units of multimeric PROTEINS. Multimeric proteins can be composed of identical or non-identical subunits. One or more monomeric subunits may compose a protomer which itself is a subunit structure of a larger assembly.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.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.Protein Interaction Domains and Motifs: Protein modules with conserved ligand-binding surfaces which mediate specific interaction functions in SIGNAL TRANSDUCTION PATHWAYS and the specific BINDING SITES of their cognate protein LIGANDS.Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Motion: Physical motion, i.e., a change in position of a body or subject as a result of an external force. It is distinguished from MOVEMENT, a process resulting from biological activity.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.Scattering, Radiation: The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Fluorescence: The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.Fluorescence Polarization: Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.Protein Unfolding: Conformational transitions of the shape of a protein to various unfolded states.Biocatalysis: The facilitation of biochemical reactions with the aid of naturally occurring catalysts such as ENZYMES.Adenosine Triphosphatases: A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.Mathematics: The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Mutation, Missense: A mutation in which a codon is mutated to one directing the incorporation of a different amino acid. This substitution may result in an inactive or unstable product. (From A Dictionary of Genetics, King & Stansfield, 5th ed)Conserved Sequence: A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.DNA, Superhelical: Circular duplex DNA isolated from viruses, bacteria and mitochondria in supercoiled or supertwisted form. This superhelical DNA is endowed with free energy. During transcription, the magnitude of RNA initiation is proportional to the DNA superhelicity.

Endocytosis: EH domains lend a hand. (1/52898)

A number of proteins that have been implicated in endocytosis feature a conserved protein-interaction module known as an EH domain. The three-dimensional structure of an EH domain has recently been solved, and is likely to presage significant advances in understanding molecular mechanisms of endocytosis.  (+info)

Membrane fusion: structure snared at last. (2/52898)

The structure of the core of the neuronal 'SNARE complex', involved in neurotransmitter release, has been determined recently. Its topological similarity to viral fusion proteins suggests how the SNARE complex might facilitate membrane fusion.  (+info)

Four dimers of lambda repressor bound to two suitably spaced pairs of lambda operators form octamers and DNA loops over large distances. (3/52898)

Transcription factors that are bound specifically to DNA often interact with each other over thousands of base pairs [1] [2]. Large DNA loops resulting from such interactions have been observed in Escherichia coli with the transcription factors deoR [3] and NtrC [4], but such interactions are not, as yet, well understood. We propose that unique protein complexes, that are not present in solution, may form specifically on DNA. Their uniqueness would make it possible for them to interact tightly and specifically with each other. We used the repressor and operators of coliphage lambda to construct a model system in which to test our proposition. lambda repressor is a dimer at physiological concentrations, but forms tetramers and octamers at a hundredfold higher concentration. We predict that two lambda repressor dimers form a tetramer in vitro when bound to two lambda operators spaced 24 bp apart and that two such tetramers interact to form an octamer. We examined, in vitro, relaxed circular plasmid DNA in which such operator pairs were separated by 2,850 bp and 2,470 bp. Of these molecules, 29% formed loops as seen by electron microscopy (EM). The loop increased the tightness of binding of lambda repressor to lambda operator. Consequently, repression of the lambda PR promoter in vivo was increased fourfold by the presence of a second pair of lambda operators, separated by a distance of 3,600 bp.  (+info)

Probing interactions between HIV-1 reverse transcriptase and its DNA substrate with backbone-modified nucleotides. (4/52898)

BACKGROUND: To gain a molecular understanding of a biochemical process, the crystal structure of enzymes that catalyze the reactions involved is extremely helpful. Often the question arises whether conformations obtained in this way appropriately reflect the reactivity of enzymes, however. Rates that characterize transitions are therefore compulsory experiments for the elucidation of the reaction mechanism. Such experiments have been performed for the reverse transcriptase of the type 1 human immunodeficiency virus (HIV-1 RT). RESULTS: We have developed a methodology to monitor the interplay between HIV-1 RT and its DNA substrate. To probe the protein-DNA interactions, the sugar backbone of one nucleotide was modified by a substituent that influenced the efficiency of the chain elongation in a characteristic way. We found that strand elongation after incorporation of the modified nucleotide follows a discontinuous efficiency for the first four nucleotides. The reaction efficiencies could be correlated with the distance between the sugar substituent and the enzyme. The model was confirmed by kinetic experiments with HIV-1 RT mutants. CONCLUSIONS: Experiments with HIV-1 RT demonstrate that strand-elongation efficiency using a modified nucleotide correlates well with distances between the DNA substrate and the enzyme. The functional group at the modified nucleotides acts as an 'antenna' for steric interactions that changes the optimal transition state. Kinetic experiments in combination with backbone-modified nucleotides can therefore be used to gain structural information about reverse transcriptases and DNA polymerases.  (+info)

A hyperstable collagen mimic. (5/52898)

BACKGROUND: Collagen is the most abundant protein in animals. Each polypeptide chain of collagen is composed of repeats of the sequence: Gly-X-Y, where X and Y are often L-proline (Pro) and 4(R)-hydroxy-L-proline (Hyp) residues, respectively. These chains are wound into tight triple helices of great stability. The hydroxyl group of Hyp residues contributes much to this conformational stability. The existing paradigm is that this stability arises from interstrand hydrogen bonds mediated by bridging water molecules. This model was tested using chemical synthesis to replace Hyp residues with 4(R)-fluoro-L-proline (Flp) residues. The fluorine atom in Flp residues does not form hydrogen bonds but does elicit strong inductive effects. RESULTS: Replacing the Hyp residues in collagen with Flp residues greatly increases triple-helical stability. The free energy contributed by the fluorine atom in Flp residues is twice that of the hydroxyl group in Hyp residues. The stability of the Flp-containing triple helix far exceeds that of any untemplated collagen mimic of similar size. CONCLUSIONS: Bridging water molecules contribute little to collagen stability. Rather, collagen stability relies on previously unappreciated inductive effects. Collagen mimics containing fluorine or other appropriate electron-withdrawing substituents could be the basis of new biomaterials for restorative therapies.  (+info)

How do peptide synthetases generate structural diversity? (6/52898)

Many low-molecular-weight peptides of microbial origin are synthesized nonribosomally on large multifunctional proteins, termed peptide synthetases. These enzymes contain repeated building blocks in which several defined domains catalyze specific reactions of peptide synthesis. The order of these domains within the enzyme determines the sequence and structure of the peptide product.  (+info)

Crystal structure of MHC class II-associated p41 Ii fragment bound to cathepsin L reveals the structural basis for differentiation between cathepsins L and S. (7/52898)

The lysosomal cysteine proteases cathepsins S and L play crucial roles in the degradation of the invariant chain during maturation of MHC class II molecules and antigen processing. The p41 form of the invariant chain includes a fragment which specifically inhibits cathepsin L but not S. The crystal structure of the p41 fragment, a homologue of the thyroglobulin type-1 domains, has been determined at 2.0 A resolution in complex with cathepsin L. The structure of the p41 fragment demonstrates a novel fold, consisting of two subdomains, each stabilized by disulfide bridges. The first subdomain is an alpha-helix-beta-strand arrangement, whereas the second subdomain has a predominantly beta-strand arrangement. The wedge shape and three-loop arrangement of the p41 fragment bound to the active site cleft of cathepsin L are reminiscent of the inhibitory edge of cystatins, thus demonstrating the first example of convergent evolution observed in cysteine protease inhibitors. However, the different fold of the p41 fragment results in additional contacts with the top of the R-domain of the enzymes, which defines the specificity-determining S2 and S1' substrate-binding sites. This enables inhibitors based on the thyroglobulin type-1 domain fold, in contrast to the rather non-selective cystatins, to exhibit specificity for their target enzymes.  (+info)

Structural basis of profactor D activation: from a highly flexible zymogen to a novel self-inhibited serine protease, complement factor D. (8/52898)

The crystal structure of profactor D, determined at 2.1 A resolution with an Rfree and an R-factor of 25.1 and 20.4%, respectively, displays highly flexible or disordered conformation for five regions: N-22, 71-76, 143-152, 187-193 and 215-223. A comparison with the structure of its mature serine protease, complement factor D, revealed major conformational changes in the similar regions. Comparisons with the zymogen-active enzyme pairs of chymotrypsinogen, trypsinogen and prethrombin-2 showed a similar distribution of the flexible regions. However, profactor D is the most flexible of the four, and its mature enzyme displays inactive, self-inhibited active site conformation. Examination of the surface properties of the N-terminus-binding pocket indicates that Ile16 may play the initial positioning role for the N-terminus, and Leu17 probably also helps in inducing the required conformational changes. This process, perhaps shared by most chymotrypsinogen-like zymogens, is followed by a factor D-unique step, the re-orientation of an external Arg218 to an internal position for salt-bridging with Asp189, leading to the generation of the self-inhibited factor D.  (+info)

The following examples show how to set up alternate conformations for structure factor calculations as well as for empirical energy calculations. The first step is to append the alternate conformations to the current molecular structure file. In this particular case, one wants to generate alternate conformations for the side chains of residues 1 and 7. alternate.inp Now one has to go to the graphics and move the alternate conformations into the correct positions. In subsequent protocols, one has to insert the following statement after reading the molecular structure file ...
Roucan, M. and Kielmann, M. and Connon, S.J. and Bernhard, S.S.R. and Senge, M.O., Conformational control of nonplanar free base porphyrins: Towards bifunctional catalysts of tunable basicity, Chemical Communications, 54, 1, 2017, 26-29 ...
TY - JOUR. T1 - Comparative Visualization of the RNA Suboptimal Conformational Ensemble In Vivo. AU - Woods, Chanin T.. AU - Lackey, Lela. AU - Williams, Benfeard. AU - Dokholyan, Nikolay V.. AU - Gotz, David. AU - Laederach, Alain. PY - 2017/7/25. Y1 - 2017/7/25. N2 - When a ribonucleic acid (RNA) molecule folds, it often does not adopt a single, well-defined conformation. The folding energy landscape of an RNA is highly dependent on its nucleotide sequence and molecular environment. Cellular molecules sometimes alter the energy landscape, thereby changing the ensemble of likely low-energy conformations. The effects of these energy landscape changes on the conformational ensemble are particularly challenging to visualize for large RNAs. We have created a robust approach for visualizing the conformational ensemble of RNAs that is well suited for in vitro versus in vivo comparisons. Our method creates a stable map of conformational space for a given RNA sequence. We first identify single point ...
TY - JOUR. T1 - Prediction of the receptor conformation for iGluR2 agonist binding. T2 - QM/MM docking to an extensive conformational ensemble generated using normal mode analysis. AU - Sander, Tommy. AU - Liljefors, Tommy. AU - Balle, Thomas. N1 - Keywords: Protein flexibility, molecular docking, normal mode analysis, elastic network model, ensemble generation, iGluR2 receptor, domain closure. PY - 2008. Y1 - 2008. KW - Former Faculty of Pharmaceutical Sciences. U2 - 10.1016/j.jmgm.2007.11.006. DO - 10.1016/j.jmgm.2007.11.006. M3 - Journal article. VL - 26. SP - 1259. EP - 1268. JO - Journal of Molecular Graphics and Modelling. JF - Journal of Molecular Graphics and Modelling. SN - 1093-3263. IS - 8. ER - ...
DynDom is a program that determines protein domains, hinge axes and amino acid residues involved in the hinge bending. It is fully automated.. You can use DynDom if you have two conformations of the same protein. These may be two X-ray structures, or structures generated using simulation techniques such as molecular dynamics or normal mode analysis.. The application of DynDom provides a view of the conformational change that is easily understood. The conformational change may be quite complicated in detail, but by using DynDom you can visualize it as involving the movement of domains as quasi-rigid bodies. The analysis of a conformational change in terms of domain movements only makes sense if the interdomain deformation is at least comparable to the intradomain deformation. You can use DynDom to assess this, but the results could be misleading if this is not the case.. DynDom allows you to visualize the domain motion in terms of the rotation of one domain relative to another. Here we see the ...
Integrins undergo large‐scale conformational changes (Springer & Dustin, 2012). In the bent‐closed (BC) conformation, the integrin ectodomain folds at knees in the α‐ and β‐subunits so that the head and upper legs associate with the lower legs (Fig 1A). In two extended states, the extended‐closed (EC) and extended‐open (EO) conformations, extension of the α‐ and β‐knees raises the headpiece above the lower legs on cell surfaces (Fig 1A). In transition from EC to EO, that is, headpiece opening, the ligand‐binding metal ion‐dependent adhesion site (MIDAS) in the β‐subunit βI domain rearranges. This reshaping of the ligand‐binding site is linked by α‐helix pistoning within the βI domain to swing of the hybrid domain away from the integrin α‐subunit (Fig 1A). Although the affinities of these states have not yet been measured, previous studies have correlated integrin adhesiveness and high affinity for ligand with the EO conformation (Takagi et al, 2002, 2003; ...
The present study on the ATP-lid of HSP90, a pharmaceutically relevant oncology target is aimed at shedding light on the differences in conformational plasticity in the presence or absence of known fragments and small molecules. Unbiased, atomistic simulations in the upper microsecond range in explicit solvent will be used to generate a large number of conformational ensembles which will serve as a basis to address the conformational preferences in terms of the induced fit or the conformational selection concept. We expect to get useful atomistic insights for designing ligands which are able to "freeze" HSP90 in a particular conformation and therefore have a higher binding affinity and residence time. The project addresses the two extremes which underlie protein-ligand interactions, namely induced fit (1) and conformational selection (2). While in the former, binding is obtained by a specific structural change, the later selects the adequate protein conformation from the unbound ensemble. The ...
Another example of the initial conformer affecting systematic results can be found by inspecting an 8 member carbon chain: "C1-C2-C3-C4-C5-C6-C7-C8". For illustrative purposes consider the central "C4-C5" bond as we rotate it 360 degrees; from -180 to 180 degrees. If one starts in the all trans conformation, we find that as we rotate the "C4-C5" bond the final conformation of 360 degrees is identical to the initial at 0 degrees. However, if the initial conformation had a number of kinks in it, we might discover that at the 120 degree mark, the C1 and C8 ran into each other. To relieve this steric problem the other dihedral angles, will relax, likely changing by more than 100 degrees and falling into new energy wells. As we continue the coordinate driving of the central C4-C5 angle to trans (180), we might find that the final conformation is not the same as the initial conformation because these other dihedrals have changed ...
Obstructing conformational shifts in active proteins keeps therapeutic guarantee biologically. of taxol in vitro and in a xenograft style of lung tumor. Also the expected mode of actions of the energetic peptides was experimentally confirmed. Both peptides destined to their mother or father protein and their natural activity was abolished in the current presence of the peptides related towards the counterpart helices. These data demonstrate a uncharacterized way for rational style of proteins antagonists previously. displays the experimentally-derived get in touch with map of HIV-1 gp41 as extracted from PDB 1ENV. The helix-helix relationships can be recognized with a peak in the total value from the Fourier transform of the get in touch with map when used on the amount by rows (or individually by columns) from the relevant 21 × 21 operating submatrix. Fig. 1illustrates the Fourier transform related to the amount of rows representing the discussion between two 21-mer sections focused around ...
iomolecules can play a significant role in the formation of nanostructured hard tissues in living organisms. These materials are formed with a degree of control that cannot yet be exerted in synthetic laboratories. To mimic these natural biomineralisation strategies, we must identify the mechanisms at work at the biomolecule-mineral interface. We will investigate, via a coupling of theory and experiment, two aspects of this interface. One aspect is how the surface can manipulate the conformation of the adsorbing biomolecule. Conformationally-labile biomolecules such as intrinsically-disordered proteins (IDPs) can change conformation upon exposure to external stimuli. Mineral surfaces provide such a stimulus that can induce folding and thus confer function(s) (such as polymorph stabilisation) related to this new conformation. Another aspect is how the adsorption of biomolecules influences the growth/stability of different crystal faces. Harnessing the ability of biomolecules to modify the growth ...
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The FCC has quietly revealed what amounts to a core componenet of its methodology for repacking TV channels in the post-incentive auction spectrum band.
1P1U: Tuning activation of the AMPA-sensitive GluR2 ion channel by genetic adjustment of agonist-induced conformational changes.
Many DNA-binding proteins (DBPs) undergo a conformational transition upon binding to cognate sites. In some cases this transition is accomplished by folding of a natively unfolded region. What is the role of this conformational transition?

The
A model for the bent conformation responsible for the regulation of the initial step of filament assembly. We propose that regulation of the initial step of fil
Please be VERY careful with this particular assay for conformational change. Not only can a protease sensitive site be uncovered by a structural change, but also a ligand-less protein CAN be more breathe-able with respect to its liganded strucuture which can have a more solid protease protected structure. Typsin can be very sneakey if given the chance. This happened to us. Turns out that by X-ray analysis and by NMR analysis, what was previously thought of as a structural change on ligand binding was actually a firming up of the fold of the protein. No residues actually changed position to any great extend. The protease protection is probably a red herring in this case. There are very well documented examples of protease protection revealing gross structural changes. Just...PLEASE BE CAREFUL with the interpretation of this assay ...
The influence of the range of the involved geometric and material parameters, such as the available area for conformational changes, the bilayer thickness, the interaction energy between transmembrane domains and lipids, is largely explored. Bounds on the available conformations experienced by the transmebrane domains are also provided.
H CHOP780101 D Normalized frequency of beta-turn (Chou-Fasman, 1978a) R LIT:2004003a PMID:354496 A Chou, P.Y. and Fasman, G.D. T Empirical predictions of protein conformation J Ann. Rev. Biochem. 47, 251-276 (1978) C PALJ810106 0.977 TANS770110 0.956 CHAM830101 0.946 CHOP780203 0.940 CHOP780216 0.929 CHOP780210 0.921 ROBB760113 0.907 GEIM800108 0.899 QIAN880133 0.897 QIAN880132 0.896 LEVM780103 0.893 PRAM900104 0.891 LEVM780106 0.890 ROBB760108 0.887 BEGF750103 0.885 ISOY800103 0.885 CRAJ730103 0.882 GEIM800111 0.878 PALJ810105 0.868 ROBB760110 0.863 NAGK730103 0.827 QIAN880131 0.824 AURR980114 -0.803 BEGF750101 -0.803 QIAN880107 -0.809 KANM800103 -0.824 AURR980109 -0.837 SUEM840101 -0.845 I A/L R/K N/M D/F C/P Q/S E/T G/W H/Y I/V 0.66 0.95 1.56 1.46 1.19 0.98 0.74 1.56 0.95 0.47 0.59 1.01 0.60 0.60 1.52 1.43 0.96 0.96 1.14 0.50 // H CHOP780201 D Normalized frequency of alpha-helix (Chou-Fasman, 1978b) R PMID:364941 A Chou, P.Y. and Fasman, G.D. T Prediction of the secondary structure of ...
1RT2: Complexes of HIV-1 reverse transcriptase with inhibitors of the HEPT series reveal conformational changes relevant to the design of potent non-nucleoside inhibitors.
The formation of complexes that have large interfaces is seen to involve large changes in conformation in those cases where native structures are available. These changes are generally described in publications reporting the X-ray structure of the complexes. They are summarised in Table 2 for the 20 complexes that have B,2000 Å^2. B=interface ...
A protein is a linear chain of amino acids that folds into a unique functional structure, called its native state. In this state, proteins show repeated substructures like alpha helices and beta sheet
Dynamic Conformational Behavior and Molecular Interaction Discrimination of DNA/Binder Complexesby Single-Chain Stretching in a MicroDevice ...
List of words make out of Conformational. All anagrams of Conformational. Words made after unscrambling Conformational. Scrabble Points. Puzzle Solver. Word Creation.
The occupancy of ions in the K+ selectivity filter: Charge balance and coupling of ion binding to a protein conformational change underlie high conduction ...
The occupancy of ions in the K+ selectivity filter: Charge balance and coupling of ion binding to a protein conformational change underlie high conduction ...
The structure of a molecule dictates its function. If you were to consider NAs, for example, they wouldnt be good enzymes since you only have a limited number of NA types as well as conformation. Which part of the NA would a reactant bind to? Same questions for CHOs and lipids. The way proteins are structured, you have so many conformations (recall 4 levels of structure) possible depending on composition. Variability in conformation among different protein molecules is important since conformation is critical in being able to bind with the reactants to enable catalysis of a reaction ...
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Functional proteins that do not have unique, stable, folded, three-dimensional native structures or that possess non-ordered regions under physiological conditions. They are characterized by extraordinary structural flexibility and plasticity, which enable them to adopt different conformations in response to different stimuli or different interactions ...
Although observed protein structures generally represent energetically favorable conformations that may or may not be \functional\, it is also generally agreed that protein structure is closely related to protein function. Given a collection of proteins s
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過去這類的分子一向被認為很難解出結晶結構3主要有幾個原因3包括分子很大(擬南芥的光敏素有一千多個氨基酸( 結構不穩定(光敏素有兩種構形conformation3分別是吸收紅光的Pr與吸收遠紅光的Pfr3而這兩種構形在光敏素與色素分子phytochromobillin結合後3就以不同比例存在4簡單來說3無法提純出100%的Pfr3也沒有100%的Pr》但是如果不跟色素分子結合得到的結晶結構也沒有意義(等因素3使得光敏素要結晶很困難4但是在將光合細菌中的光敏素取得結晶以後3科學家們由細菌的經驗3摸索出如何將高等植物的光敏素結晶的條件3於是有了擬南芥光敏素B的結晶結構(2 ...
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Conformational characterisation of peptide-1 at 10°C in the presence of TFE and SDS (A). Far-UV CD spectra at pH 4.2 as a function of TFE concentration. TFE in
where TE-PLPclose is the holo tetrameric active Trpase at 25°C in a close conformation; TE-PLPopen is the holo tetrameric enzyme in the open conformation at 2°C; TE... PLP is the non-covalently bound complex in an open conformation and TE is the apo enzyme in an open conformation at 2°C. Step 4 is the dissociation of the tetrameric form to dimers, TE to DE.. Cooling (step 1) weakens the hydrophobic interactions resulting in a conformational change and a corresponding modified solvation. The change from the closed to an open conformation is associated with a reduction in the tight packing of the tetramer and is enhanced by the point mutations. This conformational change is further supported by the present high pressure studies showing that increasing hydrostatic pressure has the same effect as decreasing temperature in affecting the conformational equilibrium.. The conformational change at low temperatures results in breaking the covalent aldimine bond between residue Lys270 (E. coli ...
Human type II transglutaminase (TG2) is an enzyme that exists in two dramatically different conformational states, each with a unique activity. In the open, extended form, the transglutaminase active site is exposed, allowing TG2 to catalyze formation of an isopeptide bond between the sidechain of a peptide-bound glutamine and a primary amine. Upon GTP binding to a separate GTPase active site, TG2 adopts a heavily favored and compact closed conformation, which obstructs the glutaminase active site, and only allows GTPase activity. TG2 has been linked to Huntingtons disease, as well as to many other cellular processes, both physiological and pathological. However, TG2s two conformational states, each with its own activity, have made it difficult to elucidate how this enzyme functions in disease progression. In addition, because TG2 heavily prefers the closed state, attempts to screen for inhibitors that may bind the transglutanimase site exposed in the open conformation, and attempts to obtain ...
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Protein dynamics play a crucial role in function, catalytic activity, and pathogenesis. Consequently, there is great interest in computational methods that probe the conformational fluctuations of a protein. However, molecular dynamics simulations are computationally costly and therefore are often limited to comparatively short timescales. TYPHON is a probabilistic method to explore the conformational space of proteins under the guidance of a sophisticated probabilistic model of local structure and a given set of restraints that represent nonlocal interactions, such as hydrogen bonds or disulfide bridges. The choice of the restraints themselves is heuristic, but the resulting probabilistic model is well-defined and rigorous. Conceptually, TYPHON constitutes a null model of conformational fluctuations under a given set of restraints. We demonstrate that TYPHON can provide information on conformational fluctuations that is in correspondence with experimental measurements. TYPHON provides a ...
en] The cold-active phosphoglycerate kinase from the Antarctic bacterium Pseudomonas sp. TACII18 exhibits two distinct stability domains in the free, open conformation. It is shown that these stability domains do not match the structural N- and C-domains as the heat-stable domain corresponds to about 80 residues of the C-domain, including the nucleotide binding site, whereas the remaining of the protein contributes to the main heat-labile domain. This was demonstrated by spectroscopic and microcalorimetric analyses of the native enzyme, of its mutants, and of the isolated recombinant structural domains. It is proposed that the heat-stable domain provides a compact structure improving the binding affinity of the nucleotide, therefore increasing the catalytic efficiency at low temperatures. Upon substrate binding, the enzyme adopts a uniformly more stable closed conformation. Substrate-induced stability changes suggest that the free energy of ligand binding is converted into an increased ...
Tel Aviv, Israel - March 18, 2008 - Compugen Ltd. (NASDAQ: CGEN) announced today the development and validation of its Blockers of Disease-Associated Conformation (DAC Blockers) platform, a new discovery platform for the identification of peptides that block proteins from adopting their disease-associated conformations. To date, two of the predicted therapeutic peptide candidates from the pilot validation run of the platform have shown initial experimental verification, one with anti-inflammatory and the other with anti-cancer activities.. The newly developed DAC Blockers platform has been designed to identify segments in proteins of interest that, if introduced therapeutically as synthetic peptides, would block specific conformational changes of such proteins, and thereby prevent them from adopting disease-associated conformations and related activities. A key capability of the platform is that it enables the proteome-wide search for such conformational change blocking peptides in human, viral ...
A procedure for automated protein structure determination is presented that is based on an iterative procedure during which the NOESY peak list assignment and the structure calculation are performed s
ClpB is a bacterial heat-shock protein that disaggregates and reactivates strongly aggregated proteins in cooperation with the DnaK chaperone system. ClpB contains two ATP-binding AAA+ modules, a linker coiled-coil domain, and a highly mobile N-terminal domain. It forms ring-shaped hexamers in a nucleotide-dependent manner. The unique aggregation reversing chaperone activity of ClpB involves ATP-dependent translocation of substrates through the central channel in the ClpB ring. The initial events of aggregate recognition and the events preceding the translocation step are poorly understood. In addition to the full-length ClpB95, a truncated isoform ClpB80, that is missing the whole N-terminal domain, is also produced in vivo. Various aspects of the structure and function of ClpB were addressed in this work. The thermodynamic stability of ClpB in its monomeric and oligomeric forms, as well as the nucleotide-induced conformational changes in ClpB were investigated by fluorescence spectroscopy. ...
Proteins are dynamic molecules. Even under native conditions, they do not adopt a single static conformation. Rather, they access many different conformations in their native state ensemble. This native state ensemble includes small fluctuations around the native conformation, partially unfolded forms, and even globally unfolded forms. The distribution of these conformations and the kinetic barriers between the conformational states define the conformational energy landscapes of proteins. My research interest is investigating conformational energy landscapes of proteins and deciphering the relationship between the energetics of proteins and their biochemical functions, such as catalysis, signal transduction, and ligand binding. We use proteolysis as a major tool to probe protein structures and dynamics as well as conventional spectroscopic methods. We also use proteomics extensively for investigating energy landscapes of proteins on a system level.. Investigation of conformational energy ...
Details: INITIAL REFINEMENT CARRIED OUT WITH TNT AND XPLOR RESIDUES B 402 - B 409 INCLUSIVE HAVE BEEN GIVEN ZERO OCCUPANCY AS THERE WAS NO INTERPRETABLE ELECTRON DENSITY IN THIS REGION. THE POSITIONS OF SIDE CHAIN ATOMS WITH TEMPERATURE FACTORS GREATER THAN 75 IS UNCERTAIN. THE MAIN CHAIN CONFORMATION IS ALSO UNCERTAIN FOR REGIONS WITH TEMPERATURE FACTORS ABOVE 60. SOLVENT MOLECULES HAVE BEEN USED TO MODEL SOME FEATURES IN THE ELECTRON DENSITY THAT ARE PROBABLY DUE TO THE "MISSING" REGIONS OF THE GAMMA SUBUNIT (CHAIN G) THE PEPTIDE BOND BETWEEN ASP 269 AND ASP 270 IN CHAINS A, B, C AND THE PEPTIDE BOND BETWEEN ASP 256 AND ASN 257 IN CHAINS D, E, AND F HAVE BEEN MODELED IN A CIS CONFORMATION. RESIDUAL FEATURES IN THE ELECTRON DENSITY MAP SUGGEST THAT THERE IS SOME CONFORMATIONAL DISORDER IN ASP 270 IN CHAINS A, B, AND C. CRYSTALS WERE GROWN IN THE PRESENCE OF AZIDE, A KNOWN INHIBITOR, BUT THIS HAS NOT BEEN LOCATED IN THE STRUCTURE ...
Abstract: Biomolecular assemblies exhibit "emergent behavior" in both the temporal and spatial domains. As observed in long-timescale molecular dynamics simulations or in 3D models of large-scale biomolecular systems, the behavior that emerges on these scales is not only more than the sum of the (temporal or spatial) parts, but quite different and unexpected. Examples include: (1) slow conformational changes in protein folding and protein-protein binding enabled by fast motion in long molecular dynamics simulations; (2) the interpretation and refinement of intermediate-resolution electron microscopy (EM) structures using multiple or flexible atomic fragments; and (3) the segmentation of the molecular building blocks of living organisms in low-resolution data from EM or tomography. The unifying goal of our efforts is to observe and to take into account functional dynamics in the native environment (solution or vitreous ice) or in silico and then to reconstruct and interpret the 3D shapes of the ...
Due to their long lifetime, triplet, redox and other transient states of fluorophores are highly sensitive to the micro-environment. Imaging their spatial distribution in biological samples can therefore help answer interesting questions about the metabolism, molecular interactions and dynamics in living cells. However, as these states are at best weakly luminescent, they have up to now only been used to a limited extent in life sciences. In Transient State (TRAST) imaging, the characteristic build up of transient states is instead monitored via fluorescence, as the excitation is modulated. When the illumination pulse width is step-wise increased, transient states are progressively populated. The resulting depletion of the singlet excited state can be monitored via time-averaged fluorescence. This fluorescence decay is characteristic for the transient state kinetics of the fluorophore in a given environment. Traditional fluorescence parameters can only be influenced within the lifetime of the ...
The present work is one of the first characterizations of multimeric intermediates in protein aggregation, and offers direct information about the assembly process. The results of the Ellman assay confirm that the dimer is linked by a disulfide bond, as previously proposed (Manderson et al. 1998; Bauer et al. 2000). Formation of the dimer therefore requires at least unfolding of the proteins main helix (Qi et al. 1997), which protects the free cysteine from the solvent in the native structure. We have previously shown that the Blg oligomers are productive intermediates in aggregation: assembly of aggregates coincides with consumption of oligomers, and purified oligomers at high concentration aggregate very rapidly (Bauer et al. 2000). The molten globule character of the oligomers observed here is perfectly in line with previous studies on other proteins (Booth et al. 1997; Kayed et al. 1999; McParland et al. 2000; Rochet and Lansbury 2000), demonstrating that aggregation is accelerated by ...
Equine conformation evaluates the degree of correctness of a horses bone structure, musculature, and its body proportions in relation to each other. Undesirable conformation can limit the ability to perform a specific task. Although there are several universal "faults," a horses conformation is usually judged by what its intended use may be. Thus "form to function" is one of the first set of traits considered in judging conformation. A horse with poor form for a Grand Prix show jumper could have excellent conformation for a World Champion cutting horse, or to be a champion draft horse. Every horse has good and bad points of its conformation and many horses (including Olympic caliber horses) excel even with conformation faults. The standard of the ideal head varies dramatically from breed to breed based on a mixture of the role the horse is bred for and what breeders, owners and enthusiasts find appealing. Breed standards frequently cite large eyes, a broad forehead and a dry head-to-neck ...
Lets look at folding in another way: You might guess a protein would fold to lowest free energy conformation. Problem: is there time? (Levinthals Paradox, formulated by Cyrus Levinthal in 1968) Stryer calculation (very conservative): Assume 100 aa residue protein with 3 possible conformations/residue; then get 3100or 5 x 1047 possible conformations. If search at a rate of one structure/10-13sec then get (5 x 1047)(10-13)= 5 x 1034 sec or 1.6 x 1027 years to search (and thus to fold protein). This is greater than the age of our Universe (13.7 x 109 yrs). [Rawn calculation (perhaps more realistic): same but assume 10 conformations, then get 1087sec or 3 x 1080 yrs!]. Obviously from these calculations not searching all possible conformations (or we have the process wrong!), so cannot say protein achieves the lowest global free energy, but rather a local free energy minima. (Like a valley in mountain range: a local energy minima, but not lowest [Marianas trench].) [sketch - note represents ...
G protein-coupled receptors (GPCRs) are membrane proteins critical in cellular signaling, making them important targets for therapeutics. The activation of GPCRs is central to their function, requiring multiple conformations of the GPCRs in their activation landscape. To enable rational design of GPCR-targeting drugs, it is essential to obtain the ensemble of atomistic structures of GPCRs along their activation pathways. This is most challenging for structure determination experiments, making it valuable to develop reliable computational structure prediction methods. In particular, since the active-state conformations are higher in energy (less stable) than inactive-state conformations, they are difficult to stabilize. In addition, the computational methods are generally biased toward lowest energy structures by design and miss these high energy but functionally important conformations. To address this problem, we have developed a computationally efficient ActiveGEnSeMBLE method that ...
Solute effects arise from PREFERENTIAL INTERACTIONS (Timasheff): Solute and water compete for the biopolymer surface Preferential Accumulation of Solute: Solute-Biopolymer interactions more favorable than interactions of both species with water Local concentration of solute higher than bulk Preferential Exclusion of Solute (Preferential Hydration) Local concentration of solute lower than bulk To describe solute distribution: Schellman 1:1 solute: water competitive binding model Our solute partitioning model; partition coefficient K p K p = m 3 loc /m 3 bulk If K p > 1, solute is accumulated; if K p < 1, solute is excluded
The creation of an automated method for determining 3D protein structure would be invaluable to the eld of biology and presents an interesting challenge to computer science. Unfortunately , given the current level of protein knowledge, a completely automated solution method is not yet feasible; therefore, our group has decided to integrate existing databases and theories to create a software system that assists X-ray crystallographers in specifying a particular protein structure. By breaking the problem of determining overall protein structure into small subproblems, we hope to come closer to solving a novel structure by solving each component. By generating necessary information for structure determination, this method provides the rst step toward designing a program to determine protein conformation automatically. The properties of a protein are largely determined by its three-dimensional structure Voet and Voet 1990]. This statement would seem to simplify the process of understanding proteins and
PINK1‐mediated phosphorylation of Ub at Ser65 has dramatic consequences for Ub structure, and key processes in the Ub system, namely Ub attachment and removal.. It could be expected that phosphorylation of Ub would change its surface properties due to the addition of a negative charge. The obtained high‐resolution crystal structure and solution studies agree that the majority of phosphoUb is structurally similar to wt Ub. To our amazement, NMR studies showed a second, minor conformation of phosphoUb, which is in slow exchange with the major conformation. Strikingly, the minor conformation shows distinct hydrogen bonding patterns and long‐range NOEs for its C‐terminal β5‐strand, which can only be structurally satisfied when this strand is shifted by two residues. Our phosphoUbretraCT model explains numerous observations and is structurally feasible due to the existence of four Leu‐Xaa repeats in the β5‐strand that would allow a shift of two residues without significantly ...
Discovering the tertiary framework of the protein, or even the quaternary structure of its complexes, can offer significant clues about how the protein performs its function. Frequent experimental methods of composition dedication consist of X-ray crystallography and NMR spectroscopy, equally of which can produce facts at atomic resolution. Our site Even so, NMR experiments can deliver information from which a subset of distances among pairs of atoms may be approximated, and the ultimate achievable conformations for a protein are determined by solving a length geometry issue. Twin polarisation interferometry can be a quantitative analytical approach for measuring the overall protein conformation and conformational modifications due to interactions or other stimulus ...
Background: Techniques for inferring the functions of the protein by comparing their shape similarity have been receiving a lot of attention. Proteins are functional units and their shape flexibility occupies an essential role in various biological processes. Several shape descriptors have demonstrated the capability of protein shape comparison by treating them as rigid bodies. But this may give rise to an incorrect comparison of flexible protein shapes. Results: We introduce an efficient approach for comparing flexible protein shapes by adapting a local diameter (LD) descriptor. The LD descriptor, developed recently to handle skeleton based shape deformations [1], is adapted in this work to capture the invariant properties of shape deformations caused by the motion of the protein backbone. Every sampled point on the protein surface is assigned a value measuring the diameter of the 3D shape in the neighborhood of that point. The LD descriptor is built in the form of a one dimensional histogram ...
Characterization of different conformational states of proteins is essential to understand their stability and activity. Biophysical techniques aid in analysing these conformational states and molecular fluorescence is one of the most reliable and quickly accessible methods. Apart from the intrinsic fluoresc
Purpose: Lacritin is a human tear glycoprotein that has high thermal stability. When cleaved, lacritin has antimicrobial activity resulting from the C-terminus amphipathic alpha helical region. The alpha helices contain three salt bridges; ionic bonds between neighboring oppositely charged amino acids. The purpose of this research was to investigate the hypothesis that the salt bridges within the alpha helices contribute to the high thermal stability. Methods: To determine the role of salt bridges in the thermal stability of lacritin, point mutants were prepared for each salt bridge by site directed mutagenesis that replaced the oppositely charged amino acids with serine. The point mutants were expressed in E. coli and purified. Western blot analysis confirmed the identity of lacritin proteins. Circular dichroism (CD) was used to study conformational changes in the secondary structure of these mutants compared to unaltered lacritin along with two controls, bovine serum albumin (BSA) and lysozyme.
Molecular recognition via noncovalent interactions plays a key role in many biological processes such as antigen-antibody interactions, protein folding, the bonding and catalytic transformation of substrates by enzymes, etc. Amongst these noncovalent interactions, electrostatic interactions, hydrogen bonding, π-π interactions, and metal-to-ligand bonding are the most prominent. Exploring noncovalent interactions in host-guest systems that range from small hydrocarbon systems to more complex systems is the main motivation of this thesis. The present study involves the design, synthesis and characterization of clip-shaped molecules as host structures, and an examination of their binding properties with a variety of guests using NMR spectroscopy.. Several clips with a hydrocarbon or glycoluril backbone were synthesized. The binding of cations to small, hydrocarbon-based clips suggests that binding is enhanced by the rigidity and cooperativity between the two sidewalls of the clip. Binding is also ...
Protein NMR is the method of choice for determining protein structures at the atomic level in solution. In addition, NMR experiments allow characterization of protein dynamics at a wide range of time scales [1-7]. Dynamical studies of the past decade led to the emerging paradigm that the so-called native structure of a protein can be better viewed as a number of more or less similar conformers interconverting on different time scales. Functional interactions perturb this state by shifting the equilibrium towards active conformations that are present but are low-populated in the apo state. The most extreme examples of this kind of behavior are provided by intrinsically disordered proteins (IDPs) that adopt a plethora of diverse conformations in their free state but, at least some of them, might become fully or partially well ordered upon partner molecule binding [8, 9].. IDPs can not be described with single-conformer models but only with conformational ensembles capturing the diversity of ...
The discovery of dilute liquid crystalline media to align biological macromolecules has opened many new possibilities to study protein and nucleic acid structures by NMR spectroscopy. We inspect the basic alignment phenomenon for an ensemble of protein conformations to deduce relative contributions of each member to the residual dipolar coupling signals. We find that molecular fluctuations can affect the alignment and discover a resulting emphasis of certain conformations. However, the internal fluctuations are largely uncorrelated with those of the alignment, implying that proteins have liquidlike molecular surfaces. Furthermore, we consider the implications of a dynamic bias to structure determination using data from the weak alignment method ...
In eukaryotic cells, proteins are translocated across the ER membrane through a continuous ribosome-translocon channel. It is unclear to what extent proteins can fold already within the ribosome-translocon channel, and previous studies suggest that only a limited degree of folding (such as the formation of isolated α-helices) may be possible within the ribosome. We have previously shown that the conformation of nascent polypeptide chains in transit through the ribosome-translocon complex can be probed by measuring the number of residues required to span the distance between the ribosomal P-site and the lumenally disposed active site of the oligosaccharyl transferase enzyme (J. Biol. Chem 271: 6241-6244).Using this approach, we now show that model segments composed of residues with strong helix-forming properties in water (Ala, Leu) have a more compact conformation in the ribosome-translocon channel than model segments composed of residues with weak helix-forming potential (Val, Pro). The main
Background. In eukaryotic cells, proteins are translocated across the ER membrane through a continuous ribosome-translocon channel. It is unclear to what extent proteins can fold already within the ribosome-translocon channel, and previous studies suggest that only a limited degree of folding (such as the formation of isolated α-helices) may be possible within the ribosome.. Results. We have previously shown that the conformation of nascent polypeptide chains in transit through the ribosome-translocon complex can be probed by measuring the number of residues required to span the distance between the ribosomal P-site and the lumenally disposed active site of the oligosaccharyl transferase enzyme (J. Biol. Chem 271: 6241-6244).Using this approach, we now show that model segments composed of residues with strong helix-forming properties in water (Ala, Leu) have a more compact conformation in the ribosome-translocon channel than model segments composed of residues with weak helix-forming potential ...
Link for Professor Gonzalez. Abstract: Over the past two decades, stunning breakthroughs in the field of structural biology have continued to produce groundbreaking high-resolution structures of large, multi-component biomolecular machines. Comparative analyses of these static structures reveals the remarkable conformational flexibility of these machines and hints at the significant structural rearrangements that evidently accompany their functional cycles. Unfortunately, the experimental observation and characterization of these conformational dynamics is severely impeded by the size and complexity of biomolecular machines, severely limiting our understanding of the contributions that dynamics make to their functions. Using a combination of molecular genetic-, biochemical-, and single-molecule biophysical approaches, my research group aims to overcome these challenges and elucidate the precise roles that the conformational dynamics of biomolecular machines play in driving and controlling their ...
The coil to globule transition is a fundamental phenomenon in the physics of macro-molecules by reason of the multiplicity of arrangements of their conformation. Such conformational freedom is the main source of entropy in the molecule and is the main opponent to the transition towards the compact state, since a system tends to the state of maximum entropy. This phenomenon is captured by very simple models, such as the ensemble of Interacting Self avoiding Walks on the lattice. This model shows that the coil to globule transition belongs to the universality class of continuous transition called Θ point. Starting from a critical inspection of the definition of the interacting walks model, we introduce a refinement aiming to represent more precisely the entropy sourced from the local fluctuations of the molecule around its equilibrium conformations; this contribution is absent in the standard model which includes only the entropy generated by the multiplicity of the global conformations. Through ...
Understanding the 3D molecular structure of proteins is of enormous importance in science, medicine and biotechnology. When determining the 3D structure of a protein using biophysical methods, it is often assumed that a protein molecule has a single, specific shape. Yet in reality, many proteins adopt a number of radically different conformations, that can interchange dynamically. Such a set of conformations is called an ensemble. It is precisely the ensemble aspect of protein structure that plays a major role in important diseases such as Parkinsons, type II diabetes or Alzheimers. Currently, there are few methods that can handle such ensembles, and the available methods are suboptimal, ad hoc and heuristic.. We have developed a statistically rigorous and computationally efficient method to determine the structure of protein ensembles (Olsson et al., J. Magn. Reson., 2010; Olsson et al., PLoS ONE, 2013), based on previous methods developed at the Bioinformatics center, targeting both NMR and ...
A technique for identifying folding patterns of proteins using mass spectrometry that is potentially faster and requires less sample than X-ray crystallographic or NMR methods has been developed by B.W. Gibson and I.D. Kuntz. They believe the time needed to determine the fold family of a protein can be reduced to one week and that less than 10mg of protein may be required to elucidate macromolecular interactions, and multiple conformational states, and to contribute to the design of protein mimetics ...
In many computational approaches to protein structure, the flexibility of amino-acid sidechains is represented via a finite set of rigid rotational isomers, known as rotamers. This representation is structurally justified (i.e. there is indeed a small set of conformations, which describe most of the flexibility of sidechains in proteins) and simplifies many of the aspects of the calculations. However, potential energies of protein conformations calculated using this so-called rotamer approximation are not necessarily in good agreement with the "true" potential energies due to the sensitivity of some energy terms to precise atomic location (see the schematic diagram below, where RCE and NCE represent the rotamer-based and true energy landscapes). The idea behind this study was to elucidate the extent to which this is a problem for such applications as computation protein design and structure prediction and to test the variety of simple "hacks" that are used in the field to address this problem ...
View Notes - Bio 1A Lect 2 Quiz from BIO 1A at Berkeley. Bio 1A Lect 2 Quiz 50% adenine aldose alpha alpha-helix amino Amino acids antiparallel beta beta-pleated sheets blood flow carbonyl cell
And indeed, thats what they find. Most of the cases they look at concern potency gains coming from putting methyls at the ortho position of a biaryl ring. Organic chemists are quite familiar with the steric, planarity-disrupting effects of ortho substituents on biaryl rings; in fact its a tried and tested strategy to improve solubility by disrupting crystal packing effects. It turns out that the bound structures of the molecules present a twisted, non-planar conformation. In the absence of methyls, the rings would prefer to stay almost coplanar (or at least less non-planar) in the unbound conformation. But putting methyl groups on twists the rings in the unbound conformation into a form thats similar to the bound one; basically theres more overlap between the solution and bound conformations in case of the methylated versions compared to the non-methylated ones. Consequently, the protein has to expend less energy to turn an already similar conformation into its bound counterpart. This ...
This book presents a novel method for clustering of protein substructures that we developed in order to study the relationships between protein sequences and their structure. We show some properties of this method and the experimental results obtained by analyzing real data from PDB (Protein Data Bank). Furthermore, we present the results of the comparison of our method and the most commonly used methods for clustering of protein structures. The main advantage of our method is its high efficiency and scalability, which are key factors for analyzing large data sets. Finally, we propose a procedure for finding sequence profiles that tend to occur in more than one structural conformation but the number of their structural conformations is limited. This procedure is based on our method for protein substructure clustering ...
In: Creighton, Thomas E. (ed.): Protein Structure : a Practical Approach. - Oxford : IRL Press , 1989 . - pp. 251-285 . - (The Practical Approach Series ; 45 ...
Bio3D-web is an online application for analyzing the sequence, structure and conformational heterogeneity of protein families. Major functionality is provided for identifying protein structure sets for analysis, their alignment and refined structure superposition, sequence and structure conservation analysis, mapping and clustering of conformations and the quantitative comparison of their predicted structural dynamics ...
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Bcl-xL is a member of the Bcl-2 family of apoptotic regulators, responsible for inhibiting the permeabilization of the mitochondrial outer membrane, and a promising anti-cancer target. Bcl-xL exists in the following conformations, each believed to play a role in the inhibition of apoptosis: (a) a soluble folded conformation, (b) a membrane-anchored (by its C-terminal α8 helix) form, which retains the same fold as in solution and (c) refolded membrane-inserted conformations, for which no structural data are available. Previous studies established that in the cell Bcl-xL exists in a dynamic equilibrium between soluble and membranous states, however, no direct evidence exists in support of either anchored or inserted conformation of the membranous state in vivo. In this in vitro study, we employed a combination of fluorescence and EPR spectroscopy to characterize structural features of the bilayer-inserted conformation of Bcl-xL and the lipid modulation of its membrane insertion transition. Our ...
Herein, we describe the synthesis of seven glycosylated adopt stable 3 novel class of functionalized foldamers in which a natural post-translational modification is attached to an unnatural peptidomimetic backbone. Conformational studies by CD spectroscopic measurements were performed in methanol and in water (pH 7). Additionally, the influence of temperature, pH, and concentration on the ability of glycosylated were investigated. The first NMR-derived solution state structure of a glycosylated water is also presented. ...
A - Tilt: 4° - Segments: 1(48-72), 2(110-131), 3(185-207), 4(210-233), 5(290-314), 6(327-348), 7(708-729), 8(748-773), 9(826-848), 10(853-874), 11(931-953), 12(970-988 ...
Iqbal, M and Balaram, P (1981) Synthesis and conformational studies of the membrane active peptide antibiotic, suzukacillin. In: Indian Journal of Biochemistry & Biophysics, 18 (4). p. 96. Full text not available from this repository ...
helix content depending on R, but the conformation changes caused by DADP are more significant than DDCP at the same R. These are related to the binding of DADP to groups other than thiols. The rate constants of conformation change suggested that DADP quenched the intrinsic fluorescence more rapid. The temporal change in fluorescence of NPM labeled actin has a biphasic feature: in the first 16 minutes, the fluorescence was quenched, then it recovered slowly, indicating a multi-step reaction including high affinity platinum binding ...
Proteins perform their function for adopting a particular 3D structure, referred as native structure, and failure to fold into the native structure has profound deleterious effects, frequently causing diseases
This is really just a postscript to the previous post. There I showed how a search of the (small molecule) crystal database revealed the s-cis conformation about the N-C amide bond (the one with partial double bond character that prevents rotation) and how this conformation means that a C-H approaches quite closely to an adjacent oxygen. It is a tiny step from that search to a related, and very famous one named after Ramachandran[1]. Indeed this search, and the contour map used to display the results, really put crystal databases on the map so to speak.. (more…). ...
MIT Professor Susan Lee Lindquist, a member and former director of the Whitehead Institute, and one of the nations most lauded scientists, has died of cancer at age 67. She made invaluable contributions to the study of protein folding, demonstrating that alternative protein conformations can have profound and unexpected influences.
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Enzymes are proteins that catalyze chemical reactions. A protein is simply a polypeptide composed of amino acids linked by a peptide bond, and the term generally, but not always, refers to the folded conformation. To understand how an enzyme functions, including its binding and functional properties, it is necessary to know the properties of the amino acids and how the amino acids are linked together, including the torsion angles of the bonds and the space occupied, and the interactions of the atoms leading to the final conformations of the folded protein. ...
In summary, the research of my laboratory is primarily on age-related degenerative diseases that are characterized by protein conformational changes. It involves studying this alteration, its consequences at the molecular- and system level, the factors that are involved in this process, as well as therapeutic and diagnostic targeting of this pathological pathway.. ...
Molecular Bilateral Symmetry of Natural Products: Prediction of Selectivity of Dimeric Molecules by Density Functional Theory and Semiempirical ...
This group of proteins is involved into signalling translation process. Usually they significantly change conformation in presence of some signalling molecules. These proteins can act as enzymes. Other proteins, usually small, can interact with receptors. Classical example of this group of proteins is GTPases ...
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Leaving aside the question of the role of genetics in behavior, the results suggest that the incidence of bloat increases with the size of the dog and the depth-to-width ratio of the chest cavity. This is a conformational problem, not a genetic disease. Certainly, the overall conformation is, ultimately, determined by the genes, but not by a single gene. There are probably dozens or hundreds of genes that go into determining the shape and size of the head, trunk, and limbs. Wherever there is genetic variability, one can select for larger, smaller, narrower, wider, etc. If the fancy as a whole decides that a taller, narrower dog looks more "refined," more of that description will be kept for breeding purposes, and the population will be shifted toward a more bloat-prone conformation ...
They bind these substrates at complementary spots on their own surfaces, supplying a snug in good shape that many experts Review to your lock and essential. site here Enzymes do the job by binding a number of substrates, bringing them jointly making sure that a response can occur, and releasing them as soon as the response is total. Especially, when substrate binding takes place, enzymes go through a conformational shift that orients or strains the substrates so that theyre additional reactive (Figure 3 ...
Fully Determined Atoms and Atoms With HAV > 1. The types of some atoms may already be fully determined at this stage; for example, HAV 4 carbons must be sp3-hybridized. Distinctions are also made on the bases of number of attached oxygens. The average of the three bond angles about each HAV 3 atom is calculated and used to assign the type of the central atom. The average bond angle has been found to be a reliable indicator of hybridization state. Only one bond angle is available for HAV 2 atoms, and this is a less reliable indicator; HAV 2 carbon and nitrogen atoms are assigned types based on the angle but are marked for further examination ...
The optree is shared between threads. This means there is a possibility that the optree will outlive the particular thread (and therefore the interpreter instance) that created it, so true Perl scalars cannot be stored in the optree. Instead a compact form is used, which can only store values that are integers (signed and unsigned), strings or ...
Probably acts as a Ca(2+) signal transducer. In response to an increase in intracellular Ca(2+) levels, binds calcium which triggers a conformational change. This conformational change allows interaction of S1001A with specific target proteins, such as TPR-containing proteins, and the modulation of their activity.
Biological molecules such as proteins can contain hundreds of thousands of atoms, which makes it very difficult to understand their function in detail. Identifying the exact atomic structure of these complex molecules is ...
Other animals are helping us understand how the human brains almost entirely flexible structure sets our intelligence apart, says John Duncan
Sugar side-chains attached to proteins have a strong folding and stabilizing effect Originally published online: April 2009 In living organisms, the correct function and activity of proteins requires their proper structure to be maintained. The saccharide side-chain of a protein, known as a glycan, is thought to be important in maintaining protein structure, activity and…
To study the details of protein molecules on the surface of a cell, a biologist would likely use a: A. scanning electron microscope B. transmission e...
Research Corridor has published a new research study titled "Circular Dichroism Spectroscopy Market - Growth, Share, Opportunities, Competitive Analysis and Forecast, 2017 - 2025". The Circular Dichroism Spectroscopy Market report studies current as well as future aspects of the Circular Dichroism Spectroscopy Market based upon factors such as market dynamics, key ongoing trends and segmentation analysis. Apart from the above elements, the Circular Dichroism Spectroscopy Market research report provides a 360-degree view of the Lipstick Packing industry with geographic segmentation, statistical forecast and the competitive landscape.. Browse the complete report at http://www.researchcorridor.com/circular-dichroism-spectroscopy-market/. Geographically, the Circular Dichroism Spectroscopy Market report comprises dedicated sections centering on the regional market revenue and trends. The Circular Dichroism Spectroscopy Market has been segmented on the basis of geographic regions into North America, ...
TY - JOUR. T1 - The conformations of trimethoprim/E. coli dihydrofolate reductase complexes A 15N and 31P NMR study. AU - Huang, Fu yung. AU - Yang, Qing Xian. AU - Huang, Tai huang. AU - Gelbaum, Leslie. AU - Kuyper, Lee F.. PY - 1991/5/20. Y1 - 1991/5/20. N2 - We have employed 15N and 31P NMR techniques to characterize the conformations of trimethoprim (TMP)/E. coli dihydrofolate reductase (DHFR) complexes in the presence and absence of NADPH and NADP+. A single conformation was observed for TMP/DHFR, NADP+/DHFR, NADPH/ DHFR and TMP/NADPH/DHFR complexes. In the ternary complex of TMP/NADP+/DHFR both the 15N and 31P spectra revealed the presence of two conformations. However, the conformations of TMP and NADP+ in the ternary complex may not be correlated, resulting in the possible existence of four conformations for the protein ternary complex.. AB - We have employed 15N and 31P NMR techniques to characterize the conformations of trimethoprim (TMP)/E. coli dihydrofolate reductase (DHFR) ...
The photosystem-II-associated 33-kDa extrinsic manganese-stabilizing protein is found in all oxygen-evolving organisms. In this paper, we show that this protein undergoes pH-induced conformational changes in the physiological pH range. At a neutral pH of 7.2, the hydrophobic amino acid residues that are most likely located inside the beta barrel are "closed" and the protein binds neither Mn2+ nor Ca2+ ions. When the protein is transferred to a solution with a slightly acidic pH of 5.7, hydrophobic amino acid residues become exposed to the surrounding medium, enabling them to bind the fluorescent probe 8,1-ANS. At this pH-induced open state, Mn2+ and Ca2+ bind to the manganese-stabilizing protein. The pH values used in this study, 7.2 and 5.7, are typical of the pH found in the thylakoid lumen in the dark and light, respectively. A model is presented in which the manganese-stabilizing protein undergoes a pH-dependent conformational change that in turn influences its capacity to bind calcium and ...
TY - JOUR. T1 - Method of determining protein conformations by the two-dimensional nuclear overhauser enhancement spectroscopy data. AU - Sherman, S. A.. AU - Andrianov, A. M.. AU - Akhrem, A. A.. PY - 1987/4. Y1 - 1987/4. N2 - A method is suggested to determine the most probable values of the angles, y of the protein backbone by the data on the availability and absence of d connectivities in the two-dimensional nuclear Overhauser enhancement spectra. In view of this, the dependences of the protonproton distances in dipeptide units of L-amino acid residues on the dihedral angles tp, y, x, are considered and the conformational states of amino acid residues of the proteins with the known spatial structure are analysed statistically. The potentialities of the method are assessed with the aid of model spectral nuclear magnetic resonance (NMR) parameters obtained from the X-ray data for the bovine pancreatic trypsin inhibitor and avian pancreatic polypeptide. It is shown that the developed procedure ...
Although the structure of Human Pancreatic Lipase has been documented through the X-ray crystallography, the knowledge about the molecular rearrangement and dynamic equilibrium in the structure (particularly in the catalytic triad and lid domains) is very scanty. The structural fluctuations and conformational changes undergo by Human Pancreatic Lipase (HPL) with and without colipase were computationally investigated through molecular dynamics simulation technique using GROMACS 2018.4, MOE 2016.0801 and VMD softwares in order to gain insight into the complex transitions at different domains. The structural stability was revealed vis-a-vis Root Mean Square Deviation (RMSD) and Root Mean Square Fluctuations (RMSF) plots. The levels of compactness/folding and conformational changes of the protein were determined using Radius of gyration and secondary analysis respectively. Salt bridge analysis gives more ionic pairs interactions than experimentally determined results. Results show that though both proteins
Protein structure prediction is an important problem in the post-genome era, which is one possible way to fill the gap between the rapid-growth sequences and the relative small number of proteins with experimentally determined structures. Despite the structural genomics initiatives and biochemical efforts, the cheapest and fastest way to obtain structural information is through prediction algorithms. Structure prediction, even in the absence of homology, is the first step of the sequence-structure-function paradigm. Great progress has been achieved in protein structure prediction during the last decades. The development of high-quality prediction methods has also been boosted by objective community-wide assessment experiments. However, the ultimate goal of protein structure prediction remains far away to reach. New algorithms, theory and advanced prediction techniques are necessary to facilitate the progress ...
When a binary mixture of ligand molecules is used to coat gold nanoparticles, stripe-like domains can occur. These nanodomains confer nanoparticles unique structure-dependent properties. The domain structure has been characterized primarily using scanning tunneling microscopy (STM) in air and in vacuum. Here we show the first STM images of striped nanoparticles in a solvent, 1-phenyloctane. We achieve stable imaging conditions on dodecanethiol hexanethiol (C12 : C6) 2 : 1 protected gold nanoparticles. These features are persistent across many images and retain their direction and overall morphology when recorded at different scan angles. We also perform small angle neutron scattering (SANS) on two hybrid C6 : C12 nanoparticle samples dissolved in chloroform. The hybrid nanoparticles have the same composition and size distribution as samples imaged with STM, but one of the two ligands (either C6 or C12) is deuterated. Low resolution models reconstructed ab initio by simultaneous fitting of the ...
Time-resolved solution scattering is a very important component of the overall efforts at BioCARS to address dynamic aspects of macromolecular function. One of the most significant advantages of X-ray solution scattering is the ability to study biological macromolecules under near-physiological conditions (pH or ionic strength, for example) in the absence of crystal packing constraints. Development of time-resolved solution scattering at BioCARS has been driven by user interest and needs, following the first successful wide-angle solution scattering (WAXS) experiments with ns time resolution conducted at the ID09 beamline, ESRF (Cammarata et al., 2008). BioCARS staff, in collaboration with Philip Anfinrud (NIH/NIDDK), implemented the infrastructure for time-resolved solution scattering experiments at 14ID beamline. The effort resulted in first solution scattering studies with 100ps time resolution (Cho et al., 2010; Kim J et al., 2011; Kim KH et al., 2011; Kim et al., 2012). In addition to the ...
List of protein structure prediction software Chou PY, Fasman GD (1974). "Prediction of protein conformation". Biochemistry. 13 ... Chou PY, Fasman GD (1978). "Empirical predictions of protein conformation". Annu Rev Biochem. 47: 251-276. doi:10.1146/annurev. ... doi:10.1093/protein/11.5.345. PMID 9681866. Chen H, Gu F, Huang Z (2006). "Improved Chou-Fasman method for protein secondary ... Kyngas J, Valjakka J (1998). "Unreliability of the Chou-Fasman parameters in predicting protein secondary structure". Protein ...
"Conformation of polypeptides and proteins". Advances in Protein Chemistry. Advances in Protein Chemistry. 23: 283-437. doi: ... Richardson, J.S. (1981). "Anatomy and Taxonomy of Protein Structures". Advances in Protein Chemistry. Advances in Protein ... Richardson, J.S. (1981). "Anatomy and Taxonomy of Protein Structures". Advances in Protein Chemistry. Advances in Protein ... Hovmöller, S.; Zhou, T.; Ohlson, T. (2002). "Conformations of amino acids in proteins". Acta Crystallographica D. 58 (Pt 5): ...
Ramachandran GN, Sasisekharan V (1968). "Conformation of polypeptides and proteins". Adv Protein Chem. Advances in Protein ... Richardson JS (1981). "The anatomy and taxonomy of protein structure". Adv Protein Chem. Advances in Protein Chemistry. 34: 167 ... Protein Common Interface Database Database of similar protein-protein interfaces in crystal structures of homologous proteins ... MMDB Protein Data Bank Structural Classification of Proteins database STING Molecular modelling List of software for molecular ...
Simplified Representation of Protein Conformations for Rapid Simulation of Protein Folding. In: Journal of Molecular Biology. ... mit J. Janin, S. Wodak, B. Maigret: The Conformation of Amino Acid Side Chains in Proteins. In: Journal of Molecular Biology. ... Protein Conformation, Dynamics and Folding by Computer Simulation. In: Annual Review of Biophysics and Bioengineering. Band 11 ... mit S. Lifson: Refinement of Protein Conformations Using a Macromolecular Energy Minimization Procedure. In: Journal of ...
The conformation of a receptor protein composes the functional state. Ligands include substrates, inhibitors, activators, and ... In protein-ligand binding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein. ... The binding typically results in a change of conformational isomerism (conformation) of the target protein. In DNA-ligand ... Ligand binding to a receptor protein alters the conformation by affecting the three-dimensional shape orientation. ...
β-Sheets predominate as the secondary level of protein conformation. Recent emergence of oseltamivir and zanamivir resistant ... There are two major proteins on the surface of influenza virus particles. One is the lectin haemagglutinin protein with three ... The first step involves the distortion of the α-sialoside from a 2C5 chair conformation (the lowest-energy form in solution) to ... which allow for secretion of FLAG-tagged proteins and further purification.[7] ...
Levitt, M. (1976). "A simplified representation of protein conformations for rapid simulation of protein folding". Journal of ... Michael Levitt publications indexed by Google Scholar Levitt, Michael (1972). Conformation analysis of proteins (PhD thesis). ... He has also worked on simplified representations of protein structure for analysing folding and packing, as well as developing ... Xia, Y.; Huang, E. S.; Levitt, M.; Samudrala, R. (2000). "Ab initio construction of protein tertiary structures using a ...
Sternberg, Michael Joseph Ezra (1977). Studies of protein conformation (DPhil thesis). University of Oxford. Phillips, D. C.; ...
Conformation analysis of proteins (1972). Pembimbing doktoral. R. Diamond. Mahasiswa doktoral. Miri Hirshberg. Chris Lee. David ... Protein structure prediction. Institusi. Stanford University. Weizmann Institute of Science. Laboratory of Molecular Biology. ...
Sibanda, B.L.; Blundell, T.L.; Thornton, J.M. (1989). "Conformation of β-hairpins in protein structures:: A systematic ... 1968). "Stereochemical criteria for polypeptides and proteins. V. Conformation of a system of three linked peptide units". ... Rajashankar KR, Ramakumar S (1996). "Pi-turns in proteins and peptides: Classification, conformation, occurrence, hydration and ... Hutchinson, E.G.; Thornton, J.M. (1994). "A revised set of potentials for β-turn formation in proteins". Protein Science. 3 (12 ...
Sibanda, BL; Blundell TL; Thornton JM (1989). "Conformation of β-hairpins in protein structures. A systematic classification ... Leader, DP; Milner-White EJ (2009). "Motivated Proteins: A web application for studying small three-dimensional protein motifs ... Chan, EAW; Hutchinson EG (1993). "Identification, classification and analysis of β-bulges in proteins". Protein Science. 2 (10 ... Two websites are available for finding and examining β bulge loops in proteins, Motivated Proteins: [1] and PDBeMotif: [2]. ...
Sibanda, B. L.; Blundell, T. L.; Thornton, J. M. (1989). "Conformation of beta-hairpins in protein structures. A systematic ... Thornton, J. M.; Singh, J; Campbell, S; Blundell, T. L. (1988). "Protein-protein recognition via side-chain interactions". ... Hubbard, Simon Jeremy (1991). Analysis of protein-protein molecular recognition (PhD thesis). University College London. EThOS ... "The Protein Feature Ontology: A tool for the unification of protein feature annotations". Bioinformatics. 24 (23): 2767-2772. ...
"An analysis of side-chain conformation in proteins". International Journal of Peptide and Protein Research. 13 (2): 170-84. ... Banerjee, R.; Das, K.; Ravishankar, R.; Suguna, K.; Surolia, A.; Vijayan, M. (7 June 1996). "Conformation, protein-carbohydrate ... side chain conformation in proteins and additional binding sites in lysozyme. Vijayan has published more than 260 peer reviewed ... "Snapshots of RecA protein involving movement of the C-domain and different conformations of the DNA-binding loops: ...
"Roles of electrostatics and conformation in protein-crystal interactions". PLoS ONE. 5 (2): e9330. doi:10.1371/journal.pone. ... Osteopontin is an extracellular structural protein and therefore an organic component of bone. Synonyms for this protein ... bone sialo protein, and alkaline phosphatase. Collagen type I counts for 90% of the protein mass. The inorganic part of bone is ... "Cooperative Unfolding of Compact Conformations of the Intrinsically Disordered Protein Osteopontin". Biochemistry. 52 (31): ...
During illumination with light, these proteins change their conformation. In the process they gain or lose their ability to ... Some fluorescent proteins can be switched on and off by light of appropriate wavelength. They can be used in a RESOLFT-type ... Just as with proteins, also some organic dyes can change their structure upon illumination. The ability to fluoresce of such ... Inducing conformational changes in proteins can be achieved already at much lower switching light intensities as compared to ...
Janin, J.; Wodak, S. (1978). "Conformation of amino acid side-chains in proteins*1". Journal of Molecular Biology. 125 (3): 357 ... In biochemistry, a Janin plot, like a Ramachandran plot, is a way to visualize dihedral angle distributions in protein ...
Durussel I, Rhyner JA, Strehler EE, Cox JA (1993). "Cation binding and conformation of human calmodulin-like protein". ... Calmodulin-like protein 3 is a protein that in humans is encoded by the CALML3 gene. GRCh38: Ensembl release 89: ... Rogers MS, Kobayashi T, Pittelkow MR, Strehler EE (2001). "Human calmodulin-like protein is an epithelial-specific protein ... 2005). "Towards a proteome-scale map of the human protein-protein interaction network". Nature. 437 (7062): 1173-8. doi:10.1038 ...
Chou, Peter Y.; Fasman, Gerald D. (1974-01-15). "Prediction of protein conformation". Biochemistry. 13 (2): 222-245. doi: ... UPF0575 protein C19orf67 is a protein which in humans (Homo sapiens) is encoded by the C19orf67 gene. Orthologs of C19orf67 are ... Protein Engineering, Design and Selection. 20 (11): 561-567. doi:10.1093/protein/gzm057. ISSN 1741-0126. "Genomatix - NGS Data ... The protein is expressed at low levels throughout the body with the exception of the testis and breast tissue. Where it is ...
Method of modifying the conformation of food and feed proteins. US Patent. G Szabolcsi, 1991. Enzimes Analizis. Akadémiai Kiadó ...
The binding typically results in a change of conformation of the target protein. In DNA-ligand binding studies, the ligand can ... The conformation of a receptor protein composes the functional state. Ligands include substrates, inhibitors, activators, and ... In protein-ligand binding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein. ... The etymology stems from ligare, which means 'to bind'. Ligand binding to a receptor protein alters the chemical conformation ...
43 (4) 482-487 (1998) ^ "Toy Model Studies of Soliton Mediated Protein Folding and Conformation Changes" Caspi, S., Ben-Jacob, ... 47, 522-527 (1999). ^ "Conformation changes and folding of proteins mediated by Davidov's soliton". Caspi, S., Ben-Jacob, E., ... Soliton Mediated Protein Folding.[17][18][19] Pattern Formation and Self-Organization.[20][21][22][23][24][25][26][27][28] In ... "Lethal protein produced in response to competition between sibling bacterial colonies". Be'er, A., Ariel, G., Kalishman, O., ...
"Ubiquitin chain conformation regulates recognition and activity of interacting proteins". Nature. 492 (7428): 266-70. doi: ... "A human protein-protein interaction network: a resource for annotating the proteome". Cell. 122 (6): 957-68. doi:10.1016/j.cell ... Polyubiquitin-C is a protein encoded by the UBC gene in humans. Polyubiquitin-C is one of the sources of ubiquitin, along with ... Chen L, Dong W, Zou T, Ouyang L, He G, Liu Y, Qi Y (August 2008). "Protein phosphatase 4 negatively regulates LPS cascade by ...
July 2003). "A prion protein epitope selective for the pathologically misfolded conformation". Nature Medicine. 9 (7): 893-9. ... The PRNP gene provides the instructions to make a protein called the prion protein (PrP). Under normal circumstances, this ... which expresses prion proteins that contort by themselves into the disease-causing conformation. Transmission occurs when ... thus being composed solely of protein material. Misshapen prion proteins carry the disease between individuals and cause ...
Sibanda, B.L.; Blundell, T.L.; Thorton, J.M. (1985). "Conformations of Beta-Hairpins in Protein Structures". Nature(London) 316 ... To see this clearly, the Pin1 Domain protein is shown to the left as an example. Proteins that are β-sheet rich, also called WW ... function by adhering to proline-rich and/or phosphorylated peptides to mediate protein-protein interactions. The "WW" refers to ... have used protein NMR to show that beta-hairpins can be formed from isolated short peptides in aqueous solution, suggesting ...
The conformation of the subunit protein in the plasma membrane caused controversy for some time. While the amino acid sequence ... Transmembrane AMPA receptor regulatory proteins (TARPs) are a family proteins that associate with AMPA receptors and control ... Myosin proteins are calcium sensitive motor proteins that have also been found to be essential for AMPA receptor trafficking. ... The first is direct phosphorylation of synaptic-associated protein 97(SAP97).[33] First, SAP-97 and Myosin-VI, a motor protein ...
"The conformation of neurotensin bound to its G protein-coupled receptor". Proceedings of the National Academy of Sciences. 100 ... He has used the technology amongst others to study the behavior of bacterial proteins, protein aggregation in Alzheimer's and ... for the analsyis of membrane embedded proteins such as G-protein coupled receptors and ion channels and for the ... permanent dead link] "University of Utrecht Orders Bruker's 527 GHz DNP-NMR System to Study Membrane Proteins". Genetic ...
Sedimentation Velocity Analysis of Heterogeneous Protein-Protein Interactions: Lamm Equation Modeling and Sedimentation ... and conformation. Samples are centrifuged with a high-density solution such as sucrose, caesium chloride, or iodixanol. The ... By 1900, it had been generally accepted that proteins were composed of amino acids; however, whether proteins were colloids or ... Howlett, G.J., Minton, A.P., Rivas, G. Analytical Ultracentrifugation for the Study of Protein Association and Assembly. ...
"Shockley-Ramo theorem measures conformation changes of ion channels and proteins". Journal of Computational Electronics. 6: 363 ... including semiconductor radiation detection and calculations of charge movement in proteins. Shockley, W. (1938). "Currents to ...
Method of determining protein conformations by the two-dimensional nuclear overhauser enhancement spectroscopy data. Journal of ... Method of determining protein conformations by the two-dimensional nuclear overhauser enhancement spectroscopy data. / Sherman ... Sherman, S. A. ; Andrianov, A. M. ; Akhrem, A. A. / Method of determining protein conformations by the two-dimensional nuclear ... Sherman, S. A., Andrianov, A. M., & Akhrem, A. A. (1987). Method of determining protein conformations by the two-dimensional ...
Optical Rotatory Dispersion and the Main Chain Conformation of Proteins. thoughts of Chemistry, Vol. I, Part III C, Polarimetry ...
Derek J. Chadwick and Kate Widdows are editors for Protein Conformation and other scientific titles. ... protein engineering and molecular modeling offer provocative insights into current views on the protein folding problem and ... Comparative Analysis of Protein Three-Dimensional Structures and an Approach to the Inverse Folding Problem (T. Blundell). ... How the amino acid sequence of a protein determines its three-dimensional structure is a major problem in biology and chemistry ...
The study of protein stability is currently undergoing a dramatic change. Early work, especially after Kauzmann (1959), ... In: Fasman G.D. (eds) Prediction of Protein Structure and the Principles of Protein Conformation. Springer, Boston, MA. * DOI ... Prediction of Protein Structure and the Principles of Protein Conformation pp 161-192 , Cite as ... Amino Acid Substitution Cross Link Protein Stability Stabilization Energy Protein Conformation These keywords were added by ...
Conformation of proteins in interfaces: Like many other substances with both hydrophilic and hydrophobic groups, soluble ... Proteins, when forming an interfacial film, are present as a monomolecular layer-i.e., a layer one molecule in height. Although ... Within the interface, proteins spread, forming thin films. Measurements of the surface tension, or interfacial tension, of such ... proteins tend to migrate into the interface between air and water or oil and water; the term oil here means a hydrophobic ...
Influence of proline residues on protein conformation.. MacArthur MW1, Thornton JM. ... an analysis has been made of all proline residues and their local conformations extracted from the Brookhaven Protein Data bank ... the influence of proline on the conformation of the preceding residue and the conformations of various proline patterns (Pro- ... We have considered the conformation of the proline itself, the relative occurrence of cis and trans peptides preceding proline ...
The Laboratory of Protein Conformation and Dynamics integrates complementary biophysical and biochemical techniques to ...
Regulation of protein kinases; controlling activity through activation segment conformation.. Nolen B1, Taylor S, Ghosh G. ... There are currently at least forty-six unique protein kinase crystal structures, twenty-four of which are available in an ... Here we examine these structures using a structural bioinformatics approach to understand how the conformation of the ...
Predicting the local structure of a protein in terms of protein blocks is the general objective of this work. A new approach, ... This form of analyzing proteins involves drafting its structure as a string of Protein Blocks. ... to scan this database and predict most probable backbone conformations for the protein local structures. Though PB-kPRED uses ... One such library, Protein Blocks, is composed of 16 standard 5-residues long structural prototypes. ...
Protein-bound conformation of a specific inhibitor against Candida albicans myristoyl-CoA:protein N-myristoyltransferase in the ...
Significance of bound water to local chain conformations in protein crystals Message Subject (Your Name) has sent you a message ... Significance of bound water to local chain conformations in protein crystals. C H Robert and P S Ho ... The fractional water occupancy of each was found by comparison of the total number of conformations in the database regardless ... We examine how the polypeptide chain in protein crystal structures exploits the multivalent hydrogen-bonding potential of bound ...
Structure of the RSV F protein in the post-fusion conformation. *DOI: 10.2210/pdb3RRT/pdb ... Here, we present the 2.8-Å crystal structure of the trimeric RSV F ectodomain in its postfusion conformation. The structure ... Mechanistically, these results suggest that 101F and motavizumab can bind to multiple conformations of the fusion glycoprotein ... The structural preservation of neutralizing epitopes in the postfusion state suggests that this conformation can elicit ...
2011) Bihelix: Towards de novo structure prediction of an ensemble of G-protein coupled receptor conformations. Proteins 80(2): ... the crystal conformation for each helix must be in that helixs top 36 conformations. The ranking of the crystal conformation ... We rely on energy ordering the final set of conformations without ligand or G protein and there could be too many nonactive ... SuperBiHelix method for predicting the pleiotropic ensemble of G-protein-coupled receptor conformations. Jenelle K. Bray, ...
... protein 3D conformation prediction at rest). PSP is defined as Protein Structure Prediction (protein 3D conformation prediction ... protein 3D conformation prediction at rest) abbreviated? PSP stands for Protein Structure Prediction ( ... PSP stands for Protein Structure Prediction (protein 3D conformation prediction at rest). ... Protein structure prediction, 2d ed. To that end, this reference sheds light on the methods used for protein structure ...
Neame, P. J. and Gallagher, J. T. (2005) Extracellular Matrix Heparan Sulfate Proteoglycans, in Amyloid Proteins: The Beta ... Sheet Conformation and Disease (ed J. D. Sipe), Wiley-VCH Verlag GmbH, Weinheim, Germany. doi: 10.1002/9783527619344.ch7 ...
Research in my lab focuses on atomic-level mechanisms of protein regulation, protein-ligand interactions, and computer-aided ... I am interested in the structure, function, and evolution of proteins and their assemblies. As Associate Dean of Research, I ... DeGrado receives Protein Societys Stein and Moore Award. Wed Feb 11, 2015 ... The award is given annually by the international society "to recognize eminent leaders in protein science who have made ...
G protein-bound conformation of mastoparan-X: heteronuclear multidimensional transferred nuclear overhauser effect analysis of ...
... the myelin basic proteins and the proteolipid proteins (DM-20/PLP). The myelin basic proteins are extrinsic membrane proteins ... The proteolipid protein gene products DM-20 and PLP are adhesive intrinsic membrane proteins that make up ≥50% of the protein ... Curiously, changes in protein conformation imparted by the PLP-specific peptide not only confer sensitivity to amino acid ... Conservation of Topology, But Not Conformation, of the Proteolipid Proteins of the Myelin Sheath. Alexander Gow, Alexander ...
In this state, proteins show repeated substructures like alpha helices and beta sheet ... A protein is a linear chain of amino acids that folds into a unique functional structure, called its native state. ... Unger, I., Moult, J.: Finding the lowest free energy conformation of a protein is an NP-hard problem: Proof and implications. ... Patton, A., Punch, W., Goodman, E.: A Standard GA approach to native protein conformation prediction. In: Proceedings of the ...
An autoinhibitory conformation of the Bacillus subtilis spore coat protein SpoIVA prevents its premature ATP-independent ... An autoinhibitory conformation of the Bacillus subtilis spore coat protein SpoIVA prevents its premature ATP-independent ... Driks A, Roels S, Beall B, Moran CP Jr & Losick R (1994) Subcellular localization of proteins involved in the assembly of the ... Ramamurthi KS & Losick R (2008) ATP-driven self-assembly of a morphogenetic protein in Bacillus subtilis. Mol Cell 31: 406-414. ...
Experimentally observed conformation-dependent geometry and hidden strain in proteins. Protein Sci. 5, 1406-1420 (1996).. ... Conformation of polypeptides and proteins. Adv. Protein Chem. 23, 283-438 (1968).. ... Sparsely populated residue conformations in protein structures: Revisiting "experimental" Ramachandran maps. Proteins Struct. ... Native proteins trap high-energy transit conformations Message Subject. (Your Name) has forwarded a page to you from Science ...
Characterizing conformation changes in proteins through the torsional elastic response. Authors: Dos Santos, Helena G.; Klett, ... The relationship between functional conformation changes and thermal dynamics of proteins is investigated with the help of the ... This article is part of a Special Issue entitled: The emerging dynamic view of proteins: Protein plasticity in allostery, ... than to pairs of conformations with the same ligands. This deep relationship between the thermal dynamics of a protein, ...
Identifying structural hotspots, understanding drug/protein or protein/protein interactions or determining the structural ... and enable biopharma researchers to gain greater insights into protein conformation and protein interactions more quickly, more ... The information and insights gained following data analysis using the HDExaminer software can be used to probe protein ... biopharmaceutical characterization requires deeper understanding of the conformational structure of biotherapeutic proteins, ...
In an example application we modeled the process of complex assembly between two proteins: Troponin C (TnC) and the N-terminal ... This way our procedure opens up a new possibility for studying mechanisms of protein complex assembly, which may be a ... CABS-dock is a versatile and efficient tool for modeling the structure, dynamics and interactions of protein complexes. The ... a phenomenon that can be modeled only when protein flexibility is properly accounted for. ...
... but not cytoplasmic protein synthesis. GA Garden, KS Canady, DI Lurie, M Bothwell and EW Rubel ... A biphasic change in ribosomal conformation during transneuronal degeneration is altered by inhibition of mitochondrial, but ... A biphasic change in ribosomal conformation during transneuronal degeneration is altered by inhibition of mitochondrial, but ... A biphasic change in ribosomal conformation during transneuronal degeneration is altered by inhibition of mitochondrial, but ...
  • Identifying such inhibitors is difficult because many protein precursors of aggregation are partially folded or intrinsically disordered, which rules out structure-based design. (ntnu.edu.tw)
  • Here we report a high-throughput method based on ion mobility spectrometry-mass spectrometry (IMS-MS) that is capable of rapidly detecting small molecules that bind to amyloid precursors, identifying the interacting protein species and defining the mode of inhibition. (ntnu.edu.tw)
  • A method is suggested to determine the most probable values of the angles, y of the protein backbone by the data on the availability and absence of d connectivities in the two-dimensional nuclear Overhauser enhancement spectra. (elsevier.com)
  • Sherman, SA , Andrianov, AM & Akhrem, AA 1987, ' Method of determining protein conformations by the two-dimensional nuclear overhauser enhancement spectroscopy data ', Journal of Biomolecular Structure and Dynamics , vol. 4, no. 5, pp. 869-884. (elsevier.com)
  • Background: Although methods based on highly abstract descriptions of protein structures, such as VAST and TOPS, can perform very fast protein structure comparison, the results can lack a high degree of biological significance. (ebscohost.com)
  • abstract = "This study reports on the preparation of riboflavin-loaded whey protein isolate (WPI) microparticles, using desolvation and then spray drying. (monash.edu)
  • abstract = "Recent experimental studies of the denatured state and theoretical analyses of the folding landscape suggest that there are a large multiplicity of low-energy, partially folded conformations near the native state. (elsevier.com)
  • abstract = "We demonstrate the fabrication of protein·gold nanoparticle (AuNP) nanocomposites in situ, leading to distinct assemblies dependent upon protein secondary structure. (elsevier.com)
  • Several novel drugs take advantage of this dynamic nature by binding to a disease-associated protein in its inactive conformation and blocking it from adopting its active form. (cgen.com)
  • In this review we will summarize these recent findings and discuss the critical role that HIV-1 envelope glycoproteins conformation plays on ADCC responses, how these responses can be measured in the laboratory, the role of HIV-1-transmission on ADCC responses and how this knowledge can be used to develop new strategies aimed at targeting HIV-1-infected cells. (nih.gov)
  • It should then be expected that T-cell recognition of protein antigens in vitro will be independent of protein conformation. (biochemj.org)
  • Our results demonstrate that the conformation of antigens in VLPs is of critical importance for optimal stimulation of protective as well as durable immune responses. (umassmed.edu)
  • Neame, P. J. and Gallagher, J. T. (2005) Extracellular Matrix Heparan Sulfate Proteoglycans, in Amyloid Proteins: The Beta Sheet Conformation and Disease (ed J. D. Sipe), Wiley-VCH Verlag GmbH, Weinheim, Germany. (wiley.com)
  • The chapters on particular amyloid proteins all keep on with a typical constitution, permitting easy access to the specified biochemical and clinical information, making this a useful software for clinicians and researchers alike. (resgate-church.com)
  • Although E2 proteins contact the two half-sites ACCG/CGGT and not the N 4 spacer, the affinity predominantly depends on the spacer base composition: as examples, a sequence containing the ACGT spacer is well-recognized by the bovine PV-E2 protein but makes low affinity target for human PV-E2, whereas the inverse is found for the AAAC spacer. (jbsdonline.com)
  • However, HIV-1 efficiently limits the exposure of those epitopes by strongly downregulating CD4 by both Nef and Vpu accessory proteins, as well as indirectly preventing the accumulation of Env at the cell surface by Vpu-mediated BST-2 antagonism. (nih.gov)
  • Significance: Our studies address how denatured conformational epitopes remain functional, provide insights into normal and disease-related prion protein, and expand epitope tagging options. (elsevier.com)
  • In the CNS of tetrapods, compact myelin is maintained as a multilamellar sheath by the combined action of two sets of highly abundant membrane proteins, the myelin basic proteins and the proteolipid proteins (DM-20/PLP). (jneurosci.org)
  • After two German chemists, Emil Fischer and Franz Hofmeister, independently stated in 1902 that proteins are essentially polypeptides consisting of many amino acids , an attempt was made to classify proteins according to their chemical and physical properties, because the biological function of proteins had not yet been established. (britannica.com)
  • A protein is a linear chain of amino acids that folds into a unique functional structure, called its native state. (springer.com)
  • The problem becomes even more challenging due to the fact that a typical protein can contain several hundreds of amino acids or several thousands of atoms. (biomedcentral.com)
  • Proteins are polymers - specifically polypeptides - formed from sequences of amino acids , the monomers of the polymer. (bioscience.ws)
  • The primary structure of a protein refers to the sequence of amino acids in the polypeptide chain. (bioscience.ws)
  • The sequence of amino acids in insulin was discovered by Frederick Sanger , establishing that proteins have defining amino acid sequences. (bioscience.ws)
  • From these frequencies a set of probability parameters were derived for the appearance of each amino acid in each secondary structure type, and these parameters are used to predict the probability that a given sequence of amino acids would form a helix, a beta strand, or a turn in a protein. (wikipedia.org)
  • Numerous studies have demonstrated that protein-ligand complexes and even large functional macromolecular protein assemblies can retain their non-covalent bonding in the gas-phase ( 1 - 4 and references therein). (pubmedcentralcanada.ca)
  • In the presence of pentameric coiled-coil proteins C and Q, which contain histidine tags and have helicities of 54 and 65%, respectively, templation of AuNP results in precipitation of the protein·AuNP composites with AuNPs 6.5 nm in diameter, creating macromolecular assemblies on the micrometer scale. (elsevier.com)
  • By manipulating protein structure via external triggers, such as TFE, we obtain control over the macromolecular conformation and overall physicochemical properties. (elsevier.com)
  • The pgp3 conformation is likely maintained by the C-terminal 75% amino acid sequence since further deletion blocked the binding by the human antibodies and two conformation-dependent mouse monoclonal antibodies. (biomedcentral.com)
  • This application note illustrates that the SYNAPT G2 HDMS System, which provides an orthogonal separation technique with ion mobility mass spectrometry, can clearly separate different conformations of equine cytochrome c within minutes, matching that of published work. (waters.com)
  • Biomolecules introduced to a mass spectrometer by electrospray ionization (ESI) exhibit a number of different conformations depending on charge states, eluent pH, and size. (waters.com)
  • Understanding the higher order structure of biomolecules is important for the biopharmaceutical industry because different conformations may affect biological activity. (waters.com)
  • It is often time-consuming to separate or identify different conformations. (waters.com)
  • Different conformations of isobaric biomolecules cannot be separated by mass spectrometric resolution alone. (waters.com)
  • This work describes how different conformations of equine cytochrome c can be clearly separated within minutes. (waters.com)
  • By selecting a single charge state of biomolecule ions, ions with different conformations can be separated. (waters.com)
  • In contrast, the channel had a low conductance (~50 pS) with no detectable ATP permeability when activated by voltage in the absence of K + . The two channel states were associated with different reactivities of the terminal cysteine of Panx1 to thiol reagents, suggesting different conformations. (sciencemag.org)
  • Proteins are dynamic entities and can adopt a series of different conformations. (cgen.com)
  • Additionally, UVRR was used to monitor changes in trp environmental hydrophobicity, hydrogen bonding, and dihedral torsion angle in different conformations of OmpA. (escholarship.org)
  • The various models capture slightly different conformations and contain complementary information which can be pooled together to capture recurrent, and therefore more likely, residue-residue contacts. (biomedcentral.com)
  • In addition, robotics-inspired algorithms depend on defining useful perturbation strategies for exploring the conformational space, which is a difficult task for large proteins because such systems are typically more constrained and exhibit complex motions. (rice.edu)
  • Since this dynamic property of proteins is important for their function in healthy and diseased states, a broad view of a protein's conformational space is crucial in many aspects of drug discovery. (cgen.com)
  • We present a hierarchical clustering and algebraic topology based method that detects regions of interest in protein conformational space. (biomedcentral.com)
  • Characterizing the conformational space of proteins is crucial for understanding the way they perform their function. (biomedcentral.com)
  • In this work we use both algebraic topology and dimensionality reduction methods to explore and characterize the conformational space of proteins. (biomedcentral.com)
  • In previous work [ 18 , 19 ] we used persistent homology to explore the conformational space of proteins and detect regions of interest that may correspond to local minima, which are hard to detect experimentally due to the relatively short time the protein spends in them. (biomedcentral.com)
  • In a C/M solution of purified proteolipid proteins, SDS did not increase the number of reactive thiol groups, but the cleavage of one disulphide bridge made it possible to alkylate six more groups. (elsevier.com)
  • As with the recently published finding for Hib-TT complexes, it is the carbohydrate component that dictates the solution behaviour of these glycoconjugates, although the lower intrinsic viscosities suggest some degree of compaction of the carbohydrate chains around the protein. (hud.ac.uk)
  • Our results confirm the hypothesis that the spacer flexibility determines the affinities for PV-E2 proteins and, moreover, precise the nature of this flexibility: a dramatic intrinsic instability of the non-contacted dinucleotide backbones. (jbsdonline.com)
  • Instrumental techniques for analyzing intrinsically disordered proteins The recently recognized phenomenon of protein intrinsic disorder is gaining significant interest among researchers, especially as the number of proteins and protein domains that have been shown to be intrinsically disordered rapidly grows. (academic.ru)
  • We also tested for the presence of translocation signals that enable insertion of these proteins into rough endoplasmic reticulum (RER) membranes. (jneurosci.org)
  • In pioneering work, Ramachandran and co-workers ( 4 ) introduced the ϕ and ψ torsion angles to describe protein backbone conformations (see Fig. 1 , A and B), defining some conformations as "allowed" and others as "disallowed" due to collisions between atoms. (sciencemag.org)
  • The core of the suite is an efficient Metropolis Monte Carlo sampler of backbone conformations in continuous three-dimensional space in atomic details. (ebscohost.com)
  • This unanticipated information lays to rest any uncertainty about whether such transitions are possible and how they occur, and in doing so lays a firm foundation for theoretical studies to better understand the transitions between basins that have been little studied but are integrally involved in protein folding and function. (sciencemag.org)
  • When antibodies from women urogenitally infected with C. trachomatis were reacted with the plasmid proteins, all 8 pORFs were positively recognized by one or more human antibody samples with the recognition of pORF5 protein (known as pgp3) by most antibodies and with the highest titers. (biomedcentral.com)
  • More importantly, the human anti-pgp3 antibodies are highly conformation-dependent. (biomedcentral.com)
  • In an example application we modeled the process of complex assembly between two proteins: Troponin C (TnC) and the N-terminal helix of Troponin I (TnI N-helix), which occurs in vivo during muscle contraction. (mdpi.com)
  • Docking simulations illustrated how the TnC molecule undergoes significant conformational transition on complex formation, a phenomenon that can be modeled only when protein flexibility is properly accounted for. (mdpi.com)
  • This way our procedure opens up a new possibility for studying mechanisms of protein complex assembly, which may be a supporting tool for rational drug design. (mdpi.com)
  • We characterized recombinant Env proteins and virus particles produced in mammalian cells that lack N-acetylglucosaminyltransferase I (GnTI), an enzyme necessary for the conversion of oligomannose N-glycans to complex N-glycans. (iavi.org)
  • The spliceosome is a large, RNA-protein complex that catalyzes pre-mRNA splicing during mRNA maturation. (wayne.edu)
  • Circular dichroism and fluorescence studies of the complex between DnaK and a thermally unstable mutant of staphylococcal nuclease indicate that the bound substrate protein is significantly unfolded. (docphin.com)
  • However, for a folded protein or a protein complex the picture may be more complex, since many bonds allow for substantial freedom and may produce an ensemble of conformations that exchange slow and can get trapped. (grantome.com)
  • The shift in loop L11 in the C-terminal domain on dehydration emulates the action responsible for the complex formation with its protein ligand biotin carboxyl carrier protein (BCCP) domain of ACCA3. (iisc.ernet.in)
  • Proteins, when forming an interfacial film, are present as a monomolecular layer-i.e., a layer one molecule in height. (britannica.com)
  • The application of lateral pressure on a protein film causes it to increase in thickness and finally to form a layer with a height corresponding to the diameter of the native protein molecule. (britannica.com)
  • The importin a3 molecule, or "car," is one of a family of importin proteins that help ferry other proteins across the nuclear membrane where they can alter the course of DNA transcription. (jefferson.edu)
  • In our SMD project we are studying the extraction of a non-covalently bound small molecule from a protein, by a user-specified tug, through any of several likely exit routes, and this is followed by batch calculations of the energetics experienced by a molecule moving naturally along such a path, i.e., by diffusion, rather than as the result of an artificial tug. (umn.edu)
  • Protein structure is the three-dimensional arrangement of atoms in an amino acid -chain molecule . (bioscience.ws)
  • In order to test whether or not Prp8 stabilizes the active-site conformation, we carried out single-molecule fluorescence resonance energy transfer (smFRET) experiments with catalytically important snRNAs U2 and U6 and Prp8. (wayne.edu)
  • Subsequently, it was established that human SAA is a 104-amino-acid molecule of which amyloid protein A corresponds to the major N-terminal part . (resgate-church.com)
  • Specifically, it is proposed that these unique ligands are able to enrich several distinct active receptor conformations, each demonstrating a preference for regulation of a discrete intracellular effector. (sciencemag.org)
  • However, various GPCRs differ sufficiently in the tilts of the TMHs that this method need not predict the optimum conformation starting from any other template. (pnas.org)
  • This suggests that inverse agonists are not merely "the opposite of agonists," but instead may serve as useful tools to investigate ligand-specific conformations of GPCRs. (sciencemag.org)
  • The activation of GPCRs is central to their function, requiring multiple conformations of the GPCRs in their activation landscape. (caltech.edu)
  • Although proteins are essential for splicing, they may not be directly involved in catalysis. (wayne.edu)
  • Therefore, it is hypothesized that Prp8 may catalyze splicing either by directly participating in catalysis or by stabilizing the conformation of the catalytically active spliceosome. (wayne.edu)
  • The fundamental event in prion diseases seems to be a conformational change in cellular prion protein (PrP C ) whereby it is converted into the pathologic isoform PrP Sc . (sciencemag.org)
  • While UPR is definitely thought to be an adaptive and protecting reaction of cells to mind-boggling ER stress the cellular response induced by protein aggregation and UPR collectively may lead to misbalance in protein folding pathway and result in. (livingseas.org)
  • This method, combining homology modeling, hierarchical complete conformational sampling, and nanosecond scale MD, provides one of the very few computational methods that predict multiple candidates for active-state conformations and is one of the most computationally affordable. (caltech.edu)
  • The term was coined in 1982 by Stanley B. Prusiner, a neurologist at the University of California at San Francisco , who proposed that a new type of pathogen consisting solely of protein is responsible for a school of deadly neurodegenerative diseases called Transmissible Spongiform Encephalopathies (TSEs). (encyclopedia.com)
  • Accumulation of proteins in aberrant conformation occurs in many neurodegenerative diseases. (livingseas.org)