Concerning the collagen triple helix:
A. It is composed of three separate α-helices that coil around each other.
B. The triple helix is stabilized by ionic bonds that occur between different strands of the helix.
C. proline residues in a single strand keep the strand in a rigid conformation
D. All of the above
E. none of the above
Collagen is a polypeptide secondary structure that can form a triple helix through strict amino acid sequence constraints. This is made of repeating Gly-X-Y units and is being shown to have adaptability to a range of proteins and functions.