THE COLLAGEN TRIPLE-HELIX STRUCTURE

Recent advances, principally through the study of peptide models, have led to an enhanced understanding of the structure and function of the collagen triple helix. In particular, the first crystal structure has clearly shown the highly ordered hydration network critical for stabi lizing both the molecular conformation and the interactions between tr iple helices. The sequence dependent nature of the conformational feat ures is also under active investigation by NMR and other techniques. T he triple-helix motif has now been identified in proteins other than c ollagens, and it has been established as being important in many speci fic biological interactions as well as being a structural element. The nature of recognition and the degree of specificity for interactions involving triple helices may differ from globular proteins. Triple-hel ix binding domains consist of linear sequences along the helix, making them amenable to characterization by simple model peptides. The appli cation of structural techniques to such model peptides can serve to cl arify the interactions involved in triple-helix recognition and bindin g and can help explain the varying im pact of different structural alt erations found in mutant collagens in diseased states.