A Novel Looping Structure of Linear Hexapeptide Boc-[D-Ala-(Z)-β-phenyldehydroalanine-L-Ala]2-OMe
Hexapeptide Boc-(D-Ala-ΔZPhe-L-Ala)2-OCH3 [Boc = tert-butyloxycarbonyl; ΔZPhe = (Z)-β-phenyldehydroalanine] in the solid state exhibited a novel looping backbone consisting of three partially overlapped β-turns supported by intramolecular (i+3) → i hydrogen bonds. Here the looping backbone also included a β-bend ribbon structure.