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A quantum mechanical study of the intrinsic helix‐forming tendency of α‐aminoisobutyric acid and dehydroalanine residues
Author(s) -
Alemán Carlos
Publication year - 1994
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.360340704
Subject(s) - dehydroalanine , chemistry , aminoisobutyric acid , helix (gastropod) , amino acid residue , stereochemistry , crystallography , amino acid , biochemistry , peptide sequence , ecology , snail , biology , gene
A quantum mechanical study to compare the ability of α‐aminoisobutyric acid (Aib), de‐hydroalanine (ΔAla), and alanine (Ala) residues to stabilize helical conformations has been performed. To address the study, the oligopeptides X n (X = Aib, ΔAla and Ala), where n varies from 1 to 6, were computed with the AM1 semiempirical method. The results show that the residues modified at the C α carbon atom, Aib and ΔAla, are better helical formers than Ala. Thus, a cooperative energy effect was found for both residues, and especially for ΔAla. These terms permit the understanding the different conformational behaviors between Ala and its C α ‐modified residues Aib and ΔAla. This trend is important for de novo protein design, where Aib and ΔAla must be considered useful residues in the design of synthetic helical motifs. © 1994 John Wiley & Sons, Inc.