Extent of Helical Induction Caused by Introducing α‑Aminoisobutyric Acid into an Oligovaline Sequence

The preferred conformations of a dodecapeptide composed of l-valine (l-Val) and α-aminoisobutyric acid (Aib) residues, Boc-(l-Val-l-Val-Aib)4-OMe (3), were analyzed in solution and in the crystalline state. Peptide 3 predominantly folded into a mixture of α- and 310-(P) helical structures in solution and a (P) α helix in the crystalline state.