Collagen Structure & Function: Difference between revisions

Collagen is a member of a family of naturally occurring proteins. It is one of the most plentiful proteins present in mammals and is responsible for performing a variety of important biological functions. It is present in large quantities in connective tissue and provides tendons and ligaments with tensile strength and skin with elasticity.It often works in conjuction with other important proteins such as keratin and elastin.

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 molecules 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 of 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.