Résumé
The highly constrained b-amino acid ABOC induces different types of helices in b urea and 1:1 a/b amide oligomers. The latter can adopt 11/9- and 18/16-helical folds depending on the chain length in solution. Short peptides alternating proteinogenic a-amino acids and ABOC in a 2:1 a/b repeat pattern adopted an unprecedented and stable 12/14/14-helix. The structure was established through extensive NMR, molecular dynamics, and IR studies. While the 1:1 a-AA/ABOC helices diverged from the canonical a-helix, the helix formed by the 9-mer 2:1 a/b-peptide allowed the projection of the a-aminoacid side chains in a spatial arrangement according to the a-helix. Such a finding constitutes an important step toward the conception of functional tools that use the ABOC residue as a potent helix inducer for biological applications.