(prolyl-hydroxylprolyl-glycine)10 and prolyl-prolyl-glycine

Heating and subsequent cooling mixtures of (Pro-Pro-Gly)(10) and (Pro-Hyp-Gly)(10) peptides leads to formation of model heterotrimeric collagen helices that can be isolated by HPLC. These heterotrimeric collagen peptide helices are shown to be fundamentally unstable as denaturing then renaturing experiments result in heterotrimeric/homotrimeric mixtures. As the proportion of hydroxyproline-containing chains in the trimers increases, differential scanning calorimetry shows that the helix melting temperatures and denaturation enthalpies increasing non-linearly. Three types of Rich-Crick hydrogen bonds observed by NMR allow modelling of heterotrimeric structures based on published homotrimeric X-ray data. This revealed a small axial movement of (Pro-Hyp-Gly)(10) chains towards the C-terminal of the helix, demonstrating heterotrimeric asymmetry.

Topics: Amino Acid Sequence; Calorimetry, Differential Scanning; Chromatography, High Pressure Liquid; Collagen; Hydrogen Bonding; Kinetics; Magnetic Resonance Spectroscopy; Models, Molecular; Oligopeptides; Peptides; Protein Binding; Protein Conformation; X-Ray Diffraction