NMR and IR conformational studies of the influence of bulky C-tetrasubstituted amino acids on Peptaibolin mimetics

Abstract

We report the conformational studies on a model peptide, Peptaibolin (Ac-Leu-Aib-Leu-Aib-Phol) and its mimetics incorporating unnatural α,α-dialkylglycines bearing longer and bulkier side chains in order to gain insight about the conformational preferences resulting from substitution of the native Aib residues. An Ala analogue was studied as a control in the conformational study. The influence imposed by the bulkier and more hydrophobic amino acids in the peptide chain was evaluated through IR spectroscopy and 1D and 2D NMR techniques, revealing certain conformational preferences.