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Structural consequences of D ‐amino acids in collagen triple‐helical peptides
Author(s) -
Shah Naina K.,
Brodsky Barbara,
Kirkpatrick Alan,
Ramshaw John A. M.
Publication year - 1999
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/(sici)1097-0282(19990405)49:4<297::aid-bip4>3.0.co;2-q
Subject(s) - chemistry , triple helix , racemization , amino acid , peptide , stereochemistry , amide , molecule , solvent , biochemistry , organic chemistry
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. © 1999 John Wiley & Sons, Inc. Biopoly 49: 297–302, 1999