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Conformational preferences of oligopeptides rich in α‐aminoisobutyric acid. I. Observation of a 3 10 /α‐helical transition upon sequence permutation
Author(s) -
Basu Gautam,
Bagchi Ken,
Kuki Atsuo
Publication year - 1991
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.360311410
Subject(s) - chemistry , sequence (biology) , helix (gastropod) , hydrogen bond , amino acid , oligopeptide , crystallography , stereochemistry , peptide , molecule , biochemistry , organic chemistry , snail , biology , ecology
The solution conformation of peptides rich in the α,α‐dialkylated amino acid Aib has proven to be a subtle problem, not because of helix/coil transitions, but rather because of α‐helical/3 10 ‐helical competition. A special series of peptides containing 75% Aib has been synthesized that feature identical amino acid composition but differing sequences; they are sequence permutation isomers. Nuclear magnetic resonance hydrogen‐bonding studies reveal that there is a sequence permutation induced transition between the two alternative helical forms within this set. The implications for the design and conformational prediction of helical Aib‐rich peptides are discussed.