Influence of different tripeptides on the stability of the collagen triple helix. II. An experimental approach with appropriate variations of a trimer model oligotripeptide

A collagen model peptide comprising three covalently cross‐linked chains (Ala‐Gly‐Pro) 8 with a stable triple‐helix conformation was utilized as the constant part of elongated model peptides of different composition. The tripeptides Gly‐Pro‐Hyp, Gly‐Pro‐Ala, Gly‐Pro‐Pro, Gly‐Pro‐Ser, Gly‐Ala‐Hyp, Gly‐Phe‐Hyp, Gly‐Glu‐Hyp, Gly‐Ala‐Lys, and Gly‐Pro‐Phe were coupled at the N‐terminal to the cross‐linked peptide. The transition temperatures determined by CD measurements are higher for the peptides containing the Gly‐X‐Hyp sequences followed by those with the Gly‐Pro‐Y sequences. In experiments with combinations of two different tripeptides coupled to the constant part of the cross‐linked model peptides higher transition temperatures were observed if the sequence of helix‐promoting tripeptides was not interrupted.