structure
Last reviewed 01/2018
A collagen molecule, which usually is combined with many other molecules to form a fibre, consists of three polypeptide chains twisted into an alpha-helix.
Each polypeptide chain is thousands of amino acids long. The sequence of amino acids is cyclical:
- three amino acids repeat
- glycine makes up every third residue
- proline is usually the second or the third residue
- the residue in any chain which is not glycine nor proline may be any other amino acid and it dictates some of the physical properties of the type of collagen