Inai Yoshihito, Ousaka Naoki, Ookouchi Yasuhiro
Department of Environmental Technology and Urban Planning, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
Biopolymers. 2006 Aug 5;82(5):471-81. doi: 10.1002/bip.20491.
Noncovalent chiral domino effect (NCDE) has been proposed as terminal-specific interaction upon a 3(10)-helical peptide chain, of which the helix sense is manipulated by an external chiral stimulus (mainly amino acid derivatives) operating on the N-terminus (Inai, Y., et al. J Am Chem Soc 2000, 122, 11731-11732; ibid., 2002, 124, 2466-2473; ibid., 2003, 125, 8151-8162). We have investigated here a helix-sense induction in an optically inactive N-terminal-free nonapeptide (1) through the screening of several peptide species that differ in chiral sequence, chain length, and C-terminal group. Helix-sense induction in peptide 1 depends largely on both the C-terminal chirality and carboxyl group in the external peptide, in which N-carbonyl-blocked amino acids, "monopeptide acids," should be the minimum requirement for effective induction. N-Protected mono- to tetrapeptides of L-Leu residue commonly induce a right-handed helix. NMR study and theoretical computation reveal that the N-terminal segment of peptide 1 binds the N-protected dipeptide molecule through multipoint coordination to induce a right-handed helix preferentially. The present findings not only will improve our understanding of the chiral roles in peptide or protein helical termini, but also might demonstrate potential applications to chirality-responsive materials based on peptide helical fragments.
非共价手性多米诺效应（NCDE）已被提出作为3(10)-螺旋肽链上的末端特异性相互作用，其中螺旋方向由作用于N端的外部手性刺激（主要是氨基酸衍生物）控制（稻井洋等人，《美国化学会志》，2000年，第122卷，11731 - 11732页；同上，2002年，第124卷，2466 - 2473页；同上，2003年，第125卷，8151 - 8162页）。我们在此通过筛选几种在手性序列、链长和C端基团方面存在差异的肽类，研究了一种无光学活性的无N端九肽（1）中的螺旋方向诱导情况。肽1中的螺旋方向诱导很大程度上取决于外部肽中的C端手性和羧基，其中N - 羰基封闭的氨基酸，即“单肽酸”，应该是有效诱导的最低要求。L - 亮氨酸残基的N - 保护单肽至四肽通常会诱导右手螺旋。核磁共振研究和理论计算表明，肽1的N端片段通过多点配位与N - 保护的二肽分子结合，优先诱导右手螺旋。本研究结果不仅将增进我们对肽或蛋白质螺旋末端手性作用的理解，还可能展示基于肽螺旋片段的手性响应材料的潜在应用。
