Structural consequences of D-amino acids in collagen triple-helical peptides

✍ Scribed by Naina K. Shah; Barbara Brodsky; Alan Kirkpatrick; John A. M. Ramshaw

• Publisher: Wiley (John Wiley & Sons)
• Year: 1999
• Tongue: English
• Weight: 76 KB
• Volume: 49
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/(sici)1097-0282(19990405)49:4<297::aid-bip4>3.0.co;2-q

✦ Synopsis

The effects of racemization of aspartic acid on triple-helical formation have been studied using a "host-guest" peptide approach where selected guest Gly-Xaa-Yaa triplets were included within a common acetyl-(Gly-Pro-Hyp) 3 -Gly-Xaa-Yaa-(Gly-Pro-Hyp) 4 -Gly-Gly-amide framework. Four guest triplets, Gly-Asp-Hyp and Gly-Asp-Ala where Asp is either L-Asp or D-Asp were studied. Thermal stability data indicated that incorporation of D-Asp residues prevented triple-helix formation in phosphate buffered saline, although triple-helical structures were formed in a stabilizing solvent, 67% aqueous ethylene glycol. In this solvent the melting temperatures of D-Asp containing peptides were more than 30°C lower than the corresponding peptides containing L-Asp. For Gly-Asp-Ala peptides, but not Gly-Asp-Hyp, peptides, melting profiles indicated that a mixture of the D-and L-Asp containing peptides were able to form heterotrimer triple-helical molecules. These studies illustrate the dramatic destabilizing effect of D-amino acids on the triple-helix stability, but indicate that they can be accommodated in this conformation.