NationMaster - Encyclopedia: Collagen helix

In collagen, the collagen helix, or type 2 helix, is a major shape in quaternary structure. It consists of a triple helix made of the repetitious amino acid sequence glycine - proline - hydroxyproline. Each of the three chains is stabilized by the steric repulsion due to the pyrrolidone rings of proline and hydroxyproline residues. The pyrrolidone rings keep out of each other’s way when the polypeptide chain assumes this extended helical form, which is much more open than the tightly coiled form of the alpha helix. The three chains are hydrogen bonded to each other. The hydrogen bond donors are the peptide NH groups of glycine residues. The hydrogen bond acceptors are the CO groups of residues on the other chains. The OH group of hydroxyproline also participates in hydrogen bonding. The rise of the collagen helix (superhelix) is 290 picometres (0.29 nm) per residue. Image File history File links Size of this preview: 800 Ã— 558 pixelsFull resolutionâ€Ž (2,400 Ã— 1,673 pixels, file size: 786 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Size of this preview: 800 Ã— 558 pixelsFull resolutionâ€Ž (2,400 Ã— 1,673 pixels, file size: 786 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... A section of a cell of Bacillus subtilis, taken with a Tecnai T-12 TEM. The scale bar is 200nm. ... Tropocollagen triple helix. ... In biochemistry, many proteins are actually assemblies of more than one protein (polypeptide) molecule, which in the context of the larger assemblage are known as protein subunits. ... A helix (pl: helices), from the Greek word ÎÎ»Î¹ÎºÎ±Ï‚/ÎÎ»Î¹Î¾, is a twisted shape like a spring, screw or a spiral (correctly termed helical) staircase. ... This article is about the class of chemicals. ... For the plant, see Glycine (plant). ... Proline is an Î±-amino acid with the chemical formula HO2CCH(NH[CH2)3]. L-Proline is one of the twenty DNA-encoded amino acids. ... Structure of hydroxyproline 4-Hydroxyproline, or hydroxyproline (C5H9O3N), is an uncommon amino acid, abbreviated as HYP, e. ... The steric effect of tri-(tert-butyl)amine makes electrophilic reactions, like forming the tetraalkylammonium cation, difficult. ... 2-Pyrrolidone is an organic compound consisting of a five-membered lactam. ... Proline is an Î±-amino acid with the chemical formula HO2CCH(NH[CH2)3]. L-Proline is one of the twenty DNA-encoded amino acids. ... Structure of hydroxyproline 4-Hydroxyproline, or hydroxyproline (C5H9O3N), is an uncommon amino acid, abbreviated as HYP, e. ... A residue, broadly, is anything left behind by a reaction or event. ... Peptides are the family of molecules formed from the linking, in a defined order, of various amino acids. ... This article is about the shape. ... Side view of an Î±-helix of alanine residues in atomic detail. ... Peptides (from the Greek Ï€ÎµÏ€Ï„Î¿Ï‚, digestible), are the family of short molecules formed from the linking, in a defined order, of various Î±-amino acids. ... For the plant, see Glycine (plant). ... Structure of hydroxyproline 4-Hydroxyproline, or hydroxyproline (C5H9O3N), is an uncommon amino acid, abbreviated as HYP, e. ...

In biochemistry and chemistry, the tertiary structure of a protein or any other macromolecule is its three-dimensional structure, as defined by the atomic coordinates. ... Side view of an Î±-helix of alanine residues in atomic detail. ... Diagram of Î²-pleated sheet with H-bonding between protein strands The Î² sheet (also Î²-pleated sheet) is the second form of regular secondary structure in proteins â€” the first is the alpha helix â€” consisting of beta strands connected laterally by three or more hydrogen bonds, forming a generally twisted, pleated sheet. ...

Categories: Protein structural motifs | Helices | Protein stubs A representation of the 3D structure of the myoglobin protein. ... Side view of an Î±-helix of alanine residues in atomic detail. ... Side view of an 310-helix of alanine residues in atomic detail. ... Side view of an Ï€-helix of alanine residues in atomic detail. ... Monomeric, left-handed Î²-helix antifreeze protein from the spruce budworm Choristoneura fumiferana (PDB accession code 1M8N). ... In proteins, a left-handed polyproline II helix (PPII, poly-Pro II) is formed when sequential residues all adopt (Ï†,Ïˆ) backbone dihedral angles of roughly (-75Â°, 150Â°) and have trans isomers of their peptide bonds. ... Diagram of Î²-pleated sheet with H-bonding between protein strands The Î² sheet (also Î²-pleated sheet) is the second form of regular secondary structure in proteins â€” the first is the alpha helix â€” consisting of beta strands connected laterally by three or more hydrogen bonds, forming a generally twisted, pleated sheet. ... A turn is an element of secondary structure in proteins. ... Cartoon representation of a Î²-hairpin The beta hairpin (or beta-beta unit) structural motif is the simplest protein motif involving two beta strands that look like a hairpin. ... A beta bulge is a localized disruption of the regular hydrogen bonding of a beta sheet, usually by inserting a residue with helical dihedral angles into one or both H-bonded Î²-strands. ... The alpha sheet (also known as an alpha pleated sheet or a polar pleated sheet) is a hypothetical secondary structure in proteins, first proposed by Linus Pauling and Robert Corey in 1951. ... A coiled coil is a structural motif found in many proteins. ... The λ repressor of bacteriophage lambda employs a helix-turn-helix to bind DNA. In proteins, the helix-turn-helix (HTH) is a major structural motif capable of binding DNA. It is composed of two α helices joined by a short strand of amino acids and is found in many... The EF hand is a helix-turn-helix structural motif in proteins. ... A representation of the 3D structure of the myoglobin protein. ... Methionine is an Î±-amino acid with the chemical formula HO2CCH(NH2)CH2CH2SCH3. ... Alanine (Ala, A) also 2-aminopropanoic acid is a non-essential Î±-amino acid. ... Leucine is one of the 20 most common amino acids and coded for by DNA. It is isomeric with isoleucine. ... Glutamic acid (Glu, E), is the protonated form of glutamate (the anion). ... Glutamine (abbreviated as Gln or Q; Glx or Z represents either glutamine or glutamic acid) is one of the 20 amino acids encoded by the standard genetic code. ... Lysine is one of the 20 amino acids normally found in proteins. ... Threonine is one of the 20 natural amino acids. ... Isoleucine is an Î±-amino acid with the chemical formula HO2CCH(NH2)CH(CH3)CH2CH3. ... Valine is an amino acid that cannot be synthesized by humans, so it is considered an essential amino acid for human life. ... Phenyl alanine is an Î±-amino acid with the formula HO2CCH(NH2)CH2C6H5. ... Tyrosine (from the Greek tyros, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese[1][2]), 4-hydroxyphenylalanine, or 2-amino-3(4-hydroxyphenyl)-propanoic acid, is one of the 20 amino acids that are used by cells... Tryptophan (abbreviated as Trp or W)[1] is one of the 20 standard amino acids, which are the building blocks of proteins, and an essential amino acid in the human diet. ... For the plant, see Glycine (plant). ... Serine (IPA ), organic compound, one of the 20 amino acids commonly found in animal proteins. ... Proline is an Î±-amino acid with the chemical formula HO2CCH(NH[CH2)3]. L-Proline is one of the twenty DNA-encoded amino acids. ... For other articles using the abbreviation or acronym asn see ASN. Asparagine is one of the 20 most common natural amino acids on Earth. ... Aspartic acid (abbreviated as Asp or D; Asx or B represent either aspartic acid or asparagine[1] ) is an Î±-amino acid with the chemical formula HO2CCH(NH2)CH2CO2H. The L-isomer is a protonated varient of one of the 20 proteinogenic amino acids, i. ... Cysteine is a naturally occurring, sulfur-containing amino acid that is found in most proteins, although only in small quantities. ... Histidine is one of the 20 most common natural amino acids present in proteins. ... Arginine (abbreviated as Arg or R)[1] is an Î±-amino acid. ... A protein primary structure is a chain of amino acids. ... In biochemistry and chemistry, the tertiary structure of a protein or any other macromolecule is its three-dimensional structure, as defined by the atomic coordinates. ...