Tertiary and Quaternary Structure
Part II. D Collagen
Collagen a fibrous protein has an unusual structure since it is a triple helix.
Figure 14. Collagen Triple Helix Structure.
This figure taken from Voet - Biochemistry - © 1990, John Wiley & Sons.
Collagen also has an unusual AA sequence:
Gly-Pro-Xxx-Gly-Pro-(OH)-Xxx
Glycine is every third residue and Hydroxy-Proline alternates with Proline at every third residues. The third residue in the trimeric sequence Gly-Pro-Xxx, can be any residue (ie Xxx).
Figure 15. Structure of Hydroxy-Proline
©Wilbur H. Campbell, 1995; wcampbel@mtu.edu