Disulfide-Bridged Heterotrimeric Collagen Peptides Containing the Collagenase Cleavage Site of Collagen Type I. Synthesis and Conformational Properties

Abstract

Collagenous peptides containing the collagenase cleavage site α1(772−784) and α2(772−784) of collagen type I were synthesized and assembled into heterotrimers via regioselective C-terminal interchain-disulfide bridging in a defined α1α2α1‘ staggered register of the three peptide strands. Various approaches were attempted to induce and stabilize the collagen-characteristic triple-helical fold even in the sequence portion of the collagenase cleavage site with its weak triple-helix propensity. By N-terminal chain elongation with (Gly-Pro-Hyp)n tripeptide repeats, particularly with n = 5, and in an even more pronounced manner, by incorporation of an additional tripeptide repeat adjacent to the cystine knot, a collagenous heterotrimer was obtained which was found to exhibit dichroic properties fully consistent with the triple-helical fold. Thermal denaturation revealed a remarkable stability with a melting temperature of 41 °C. Although the complex cystine knot of natural collagen was reduced in these syntheti...