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Conformational preferences of oligopeptides rich in α‐aminoisobutyric acid. II. A model for the 3 10 /α‐helix transition with composition and sequence sensitivity
Author(s) -
Basu Gautam,
Kuki Atsuo
Publication year - 1992
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.360320109
Subject(s) - chemistry , helix (gastropod) , hydrogen bond , sequence (biology) , folding (dsp implementation) , crystallography , transition (genetics) , stereochemistry , molecule , biochemistry , organic chemistry , ecology , snail , gene , electrical engineering , biology , engineering
The analysis of the factors that control the helical folding of Aib‐rich peptides is extended to include sensitivity to sequence patterns, and in particular the presence of contiguous non‐Aib α‐mono‐alkylated residues. The distinct hydrogen‐bonding network of the 3 10 −helix, as contrasted with that of the competing α‐helical structure, is explicitly incorporated into a theoretical model for the 3 10 −helix/α‐helix equilibrium constant for a given peptide. Finite length effects and the “extra” intrahelical hydrogen bond of the 3 10 form are expressed naturally as a result of this loop analysis. This semiempirical model captures all the established features of existing empirical rules for helical conformational transitions in Aib‐rich sequences, as well as the recently detected helical transition induced solely by sequence permutation.