Triple-Helical Structure of Collagen Based on Single-Crystal Analyses of Model Peptides

Abstract

Recent structure analyses of collagen-model peptides revealed several important structural features of collagen. (1) Contrary to the Rich and Crick 10/3-helix, the 7/2-helical conformation is preferable as a structure of collagen. (2) The triple-helical structure is stabilized by a repetitive X (C=O) --- HN (Gly) hydrogen bonds. If X is not Pro or Hyp, the water-bridge, Gly (C=O) --- H₂O --- HN (X), also stabilize the triple-helical structure. (3) The stabilization of collagen by Hyp can be attributed to the inductive effect of the hydroxyl moiety attached to the Cγ of Pro.