Secondary structure

Collagen helix

Collagen is a fibrous protein, the major component of the connective tissue, skin, tendons, cartilage and bones. In collagen we can find a singular secondary structure, helicoidal but more stretched or elongated than alpha helix and turning left instead of right-handed. This structure is called collagen helix.

Its sequence presents a characteristic repeat of Gly–X–Y, where X is usually proline and Y is usually proline or hydroxyproline.

Gly Pro Hyp
(Note: the central residue in this model is alanine rather than glycine.)

As we'll see further on (quaternary structure), this repetitive sequence is essential for the association of collagen chains, fiber formation and, finally, function of this protein.

to perceive the polypeptide structure.

Colour the peptide backbone.

To perceive the left-handed (or sinistrorse) direction of this helix, click .