Collagen Structure & Function: Difference between revisions
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The shape and structural properties of a native collagen molecule are established by its triple-helical domain(s). In classical collagen molecules a single triple-helical domain is observed to compose close to 95% of the molecule <ref>PMID: 19853297</ref>. However there are also other types of collagens that have been shown to comprise of multiple triple-helical domains which only account for a fraction of the molecule's overall mass. | The shape and structural properties of a native collagen molecule are established by its triple-helical domain(s). In classical collagen molecules a single triple-helical domain is observed to compose close to 95% of the molecule <ref>PMID: 19853297</ref>. However there are also other types of collagens that have been shown to comprise of multiple triple-helical domains which only account for a fraction of the molecule's overall mass. | ||
The triple-helical domain of collagens consist of three distinct α-chains. Each of these chains contain a characteristic L-handed amino acid sequence of polyproline, often termed as polyproline type II helix <ref>PMID: 19344236</ref>. The proper folding of each of these chains requires a glycine residue to be present in every third position in the polypeptide chain. For example, each α-chain is composed of multiple triplet sequences of of Gly-Y-Z in which Y and Z can be any amino acid. Y is commonly found as proline and Z as hydroxyproline. The presence of hydroxyproline in the Y position contributes to the stability of the helical form. | The triple-helical domain of collagens consist of three distinct α-chains and earns collagen the name "tropocollagen". Each of these chains contain a characteristic L-handed amino acid sequence of polyproline, often termed as polyproline type II helix <ref>PMID: 19344236</ref>. The proper folding of each of these chains requires a glycine residue to be present in every third position in the polypeptide chain. For example, each α-chain is composed of multiple triplet sequences of of Gly-Y-Z in which Y and Z can be any amino acid. Y is commonly found as proline and Z as hydroxyproline. The presence of hydroxyproline in the Y position contributes to the stability of the helical form. | ||
These three chains are then twisted around one another in a rope-like manner to produce the overall tightly packed triple-helical form of the molecule. The interaction of α-chains is stabilized via interchain hydrogen bonding making the molecule fairly resistant to attack by other molcules. This hydrogen bonding occurs when the amino group (NH) of a glycine residue forms a peptide bond with the carbonyl (C=0) of an adjacent residue. The overall molecule is approxiametly 300nm long and 1.5-2nm in diameter .<ref name="collalike">PMID:7695699</ref>. | These three chains are then twisted around one another in a rope-like manner to produce the overall tightly packed triple-helical form of the molecule. The interaction of α-chains is stabilized via interchain hydrogen bonding making the molecule fairly resistant to attack by other molcules. This hydrogen bonding occurs when the amino group (NH) of a glycine residue forms a peptide bond with the carbonyl (C=0) of an adjacent residue. The overall molecule is approxiametly 300nm long and 1.5-2nm in diameter .<ref name="collalike">PMID:7695699</ref>. | ||