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Heterochiral Ala/( αMe)Aze sequential oligopeptides: S ynthesis and conformational study
Author(s) -
Drouillat Bruno,
Peggion Cristina,
Biondi Barbara,
Wright Karen,
Couty François,
Crisma Marco,
Formaggio Fernando,
Toniolo Claudio
Publication year - 2019
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.3165
Subject(s) - random hexamer , chemistry , dimer , dipeptide , stereochemistry , peptide , peptide bond , disulfide bond , oligopeptide , amide , crystallography , biochemistry , organic chemistry
α‐Amino acid residues with a ϕ,ψ constrained conformation are known to significantly bias the peptide backbone 3D structure. An intriguing member of this class of compounds is (αMe)Aze, characterized by an N α ‐alkylated four‐membered ring and C α ‐methylation. We have already reported that ( S )‐(αMe)Aze, when followed by ( S )‐Ala in the homochiral dipeptide sequential motif ‐( S )‐(αMe)Aze‐( S )‐Ala‐, tends to generate the unprecedented γ‐bend ribbon conformation, as formation of a regular, fully intramolecularly H‐bonded γ‐helix is precluded, due to the occurrence of a tertiary amide bond every two residues. In this work, we have expanded this study to the preparation and 3D structural analysis of the heterochiral ( S )‐Ala/( R )‐(αMe)Aze sequential peptides from dimer to hexamer. Our conformational results show that members of this series may fold in type‐II β‐turns or in γ‐turns depending on the experimental conditions.