Heterochiral Ala/(αMe)Aze sequential oligopeptides: Synthesis and conformational study

Bruno Drouillat (1) , Cristina Peggion (2) , Barbara Biondi (3) , Karen Wright (1) , François Couty (1) , Marco Crisma (3) , Fernando Formaggio (3) , Claudio Toniolo (2)

1 ILV - Institut Lavoisier de Versailles
2 Dipartimento di Scienze Chimiche [Padova]
3 ICB - Istituto di chimica biomolecolare [Padova, Italy]

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 Nα‐alkylated four‐membered ring and Cα‐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.

Domaines: Chimie organique

Bruno Drouillat, Cristina Peggion, Barbara Biondi, Karen Wright, François Couty, et al.. Heterochiral Ala/(αMe)Aze sequential oligopeptides: Synthesis and conformational study. Journal of Peptide Science, 2019, 16th Naples Workshop on Bioactive Peptides: ‘The exciting role of Peptides in life science’ May 2019, 25 (5), pp.e3165. ⟨10.1002/psc.3165⟩. ⟨hal-02348748⟩