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Conformational studies of N ‐acetyl‐ N ′‐methylamide derivatives of α‐aminobutyric acid, norvaline, and valine. I. Preferred conformations in solution as studied by 1 H‐nmr spectroscopy
Author(s) -
Yamazaki Toshimasa,
Abe Akihiro
Publication year - 1988
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.360270607
Subject(s) - chemistry , conformational isomerism , stereochemistry , moiety , nuclear magnetic resonance spectroscopy , dihedral angle , norvaline , vicinal , protonation , molecule , crystallography , valine , hydrogen bond , amino acid , organic chemistry , ion , biochemistry
The 1 H‐nmr studies were extensively carried out to elucidate preferred conformations of dipeptides CH 3 C*O—X—NHCH 3 , with X = Abu, nVal, and Val in various solvents. The vicinal 1 H— 1 H coupling constants for the NH—C α H moiety and those around the C α —C β bond in the articulated side chain provided the information regarding the average conformation of these molecules. The results indicate that transformation of skeletal conformations takes place in solution among conformers having similar dihedral angles, θ HN—C α H , in the Karplus expression.