A New Molecular Scaffold for the Formation of Supramolecular Peptide Double Helices: The Crystallographic Insight

A series of water-soluble synthetic dipeptides (1−3) with an N-terminally located β-alanine residue, β-alanyl-l-valine (1), β-alanyl-l-isoleucine
(2), and β-alanyl-l-phenylalanine (3), form hydrogen-bonded supramolecular double helices with a pitch length of 1 nm, whereas the C-terminally
positioned β-alanine containing dipeptide (4), l-phenylalanyl-β-alanine, does not form a supramolecular double helical structure. β-Ala-Xaa
(Xaa = Val/Ile/Phe) can be regarded as a new motif for the formation of supramolecular double helical structures in the solid state.

一系列水溶性合成二肽（1~3）的氨基端（N端）带有β-丙氨酸残基，分别为β-丙氨酰-L-缬氨酸（1）、β-丙氨酰-L-异亮氨酸（2）与β-丙氨酰-L-苯丙氨酸（3），可形成螺距为1 nm的氢键结合型超分子双螺旋（supramolecular double helix）；而含羧基端（C端）β-丙氨酸的二肽（4）即L-苯丙氨酰-β-丙氨酸，则无法形成该类超分子双螺旋结构。β-Ala-Xaa（Xaa = Val/Ile/Phe）可被视为固态环境下构建超分子双螺旋结构的新型基序（motif）。