title: Effects of the stereo-configuration of the hydroxyl group in 4-hydroxyproline on the triple-helical structures formed by homogenous peptides resembling collagen.
abstract: To explore further the recent demonstration that hydroxyproline stabilizes the triple-helical structure of collagen, two peptides containing allohydroxyproline, (aHyp-Pro-Gly)10 and (Pro-aHyp-Gly)10, were synthesized by a modified Merrifield technique which yields products of defined molecular weight. Examination of the peptides by optical rotation and circular dichroism showed that neither of them formed triple-helical structures in aqueous solution. Since the peptides had less tendency than (Pro-Hyp-Gly)10 to become helical, the results demonstrated that the trans-4-hydroxyl group of hydroxyproline makes a specific contribution to stability of the triple helix formed by (Pro-Hyp-Gly)10. Since the peptides also had less tendency than (Pro-Pro-Gly10 to become helical, the results further demonstrated that the cis-4-hydroxyl group on allohydroxyproline decreases the stability of the triple helix. The observations provided direct support for previous data indicating that incorporation of proline analogues such as allohydroxyproline into pro-alpha chains during procollagen biosynthesis prevents the polypeptides from becoming triple helical.
mesh_terms: D001665:Binding Sites; D002942:Circular Dichroism; D003094:Collagen; D006909:Hydroxyproline / Q000032:analysis; D008968:Molecular Conformation; D009842:Oligopeptides; D009904:Optical Rotation; D011485:Protein Binding; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D009842:Oligopeptides; D003094:Collagen; D006909:Hydroxyproline