Ousaka Naoki, Inai Yoshihito, Okabe Takahiro
Department of Environmental Technology and Urban Planning, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
Biopolymers. 2006 Nov;83(4):337-51. doi: 10.1002/bip.20557.
Chiral interaction of helical peptide with chiral molecule, and concomitant induction in its helix sense have been demonstrated in optically inactive nonapeptide (1) possessing Gly at its N-terminus: H-Gly-(Delta(Z)Phe-Aib)(4)-OCH(3) (1: Delta(Z)Phe = Z-dehydrophenylalanine; Aib = alpha-aminoisobutyric acid). Spectroscopic measurements [mainly nuclear magnetic resonance (NMR) and circular diochroism (CD)] as well as theoretical simulation have been carried out for that purpose. Peptide 1 in the 3(10)-helix tends to adopt preferentially a right-handed screw sense by chiral Boc-L-amino acid (Boc: t-butoxycarbonyl). Induction in the helix sense through the noncovalent chiral domino effect should be derived primarily from the complex supported by the three-point coordination on the N-terminal sequence. Thus the 3(10)-helical terminus consisting of only alpha-amino acid residues enables chiral recognition of the Boc-amino acid molecule, leading to modulation of the original chain asymmetry. Dynamics in the helix-sense induction also have been discussed on the basis of a low-temperature NMR study. Furthermore, the inversion of induced helix sense has been achieved through solvent effects.
在N端含有甘氨酸的非光学活性九肽（1）：H-Gly-(Δ(Z)Phe-Aib)₄-OCH₃（1：Δ(Z)Phe = Z-脱氢苯丙氨酸；Aib = α-氨基异丁酸）中，已证实螺旋肽与手性分子的手性相互作用以及随之而来的螺旋方向诱导。为此进行了光谱测量[主要是核磁共振（NMR）和圆二色性（CD）]以及理论模拟。在3(10)-螺旋中的肽1倾向于优先通过手性Boc-L-氨基酸（Boc：叔丁氧羰基）采用右手螺旋方向。通过非共价手性多米诺效应在螺旋方向上的诱导应主要源于由N端序列上的三点配位所支持的复合物。因此，仅由α-氨基酸残基组成的3(10)-螺旋末端能够对手性Boc-氨基酸分子进行手性识别，从而导致原始链不对称性的调节。还基于低温NMR研究讨论了螺旋方向诱导中的动力学。此外，通过溶剂效应实现了诱导螺旋方向的反转。
