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Theoretical conformational analysis of a μ‐selective cyclic opioid peptide analog
Author(s) -
Wilkes Brian C.,
Schiller Peter W.
Publication year - 1987
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.360260817
Subject(s) - chemistry , side chain , conformational isomerism , residue (chemistry) , stereochemistry , peptide , molecular mechanics , molecule , energy minimization , cyclic peptide , computational chemistry , organic chemistry , polymer , biochemistry
The allowed conformations of the μ‐receptor‐selective cyclic opioid peptide analogwere determined using a grid search through the entire conformational space. Energy minimization of the 13‐membered ring structure lacking the exocyclic Tyr 1 residue and the Phe 3 side chain using the molecular mechanics program Maximin resulted in only four low‐energy conformations. These four ring structures served as templates for a further energy minimization study with the Tyr 1 residue and Phe 3 side chain added to the molecule. The results indicated that the Tyr 1 and Phe 3 side chains enjoy considerable orientational freedom, but nevertheless, only a limited number of low‐energy side‐chain configurations were found. The obtained low‐energy conformers are discussed in relation to various proposed models of the bioactive conformation of enkephalins and morphiceptin.