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A triple‐helical model for (Gly‐Pro‐Hyp) n with cis peptide units
Author(s) -
Bansal M.,
Ramakrishnan C.,
Ramachandran G. N.
Publication year - 1975
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/bip.1975.360141203
Subject(s) - chemistry , tripeptide , triple helix , hydroxyproline , hydrogen bond , peptide , collagen helix , stereochemistry , sequence (biology) , crystallography , molecule , organic chemistry , biochemistry
Synthetic regular polytripeptides of the type (Gly‐R 2 ‐R 3 ) where R 2 , R 3 , or both, are imino acids have been widely studied as model compounds for collagen. One such polytripeptide is poly(Gly‐Pro‐Hyp), since triplets with this sequence constitute about 10% of collagen. Recently, a new model has been proposed for this polytripeptide in which one of the three peptide bonds in the tripeptide unit is in the cis conformation, and the γ‐hydroxyl group of hydroxyproline forms a direct interchain hydrogen bond within the triple helix. We have confirmed this structure by model building using computer techniques, and the helical parameters obtained by us are close to the experimentally observed values. The model is also found to be comparable in stability with other models from energy considerations.