Induction of one-handed helical screw sense in achiral peptide through the domino effect based on interacting its N-terminal amino group with chiral carboxylic acid
Induction of one-handed helical screw sense in achiral peptide through the domino effect based on interacting its N-terminal amino group with chiral carboxylic acid
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DOI：
10.1021/ja0026096
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发表时间：
2000-11-29
影响因子：
15
通讯作者：
Yamashita, M
中科院分区：
文献类型：
--
作者：
Inai, Y;Tagawa, K;Yamashita, M
螺旋链是生物聚合物中最常见的二级结构，当手性部分通过共价键并入主链或侧链时，螺旋链优选单手（左手或右手）螺旋方向。我们在这里报告的非手性螺旋肽喜欢单手螺旋的意义，其N-末端的氨基与手性羧酸的非共价相互作用。关于生物聚合物典型的肽系统中的这种现象知之甚少，尽管已经报道了在重复单元中带有羧基或氨基的合成螺旋聚合物通过添加手性小胺或酸以在其聚合物侧或主链上相互作用而诱导单手螺旋感。1在我们的系统中，发生在肽链N-末端位置的酸碱相互作用将导致整个肽链的单手螺旋感占优势，即通过多米诺效应。为了我们的目的，合成了以下由非蛋白质氨基酸[R-氨基异丁酸（Aib）和R，-脱氢苯丙氨酸（ΔZPhe）]组成的N-去保护的九肽1。2由于Aib和ΔZPhe残基是非手性残基，是形成310-螺旋的强诱导剂，因此可以预期肽1产生两个“对映体”（左手和右手）螺旋。3实际上，通过1H NMR光谱在CDCl 3中的肽1上证明了螺旋构象。在NOESY实验中，观察到NiH-Ni+ 1H共振的明显交叉噪声，
A helical chain being the most common secondary structure in biopolymers prefers one-handed (left-or right-handed) screw sense, when chiral moieties are incorporated into the main or side chain through the covalent bond. We here report that an achiral helical peptide prefers the one-handed helical screw sense by noncovalent interaction of its N-terminal amino group with a chiral carboxylic acid. Little is known about such phenomena in peptide systems typical of biopolymers, although it has been reported that synthetic helical polymers bearing carboxyl or amino groups in the repeating units induce the one-handed screw sense by addition of chiral small amines or acids to interact on their polymer side or main chains. 1 In our system, the acid-base interaction occurring in the N-terminal position of the peptide chain will lead to the predominance of one-handed screw sense of the entire peptide chain, namely through domino effect. For our purpose, the following N-deprotected nonapeptide 1 consisting of nonprotein amino acids [R-aminoisobutyric acid (Aib) and R,-dehydrophenylalanine (ΔZPhe)] was synthesized. 2Peptide 1 can be expected to generate two “enantiomeric”(leftand right-handed) helices, since Aib and ΔZPhe residues are achiral ones and strong inducers for forming a 310-helix. 3 Actually, a helical conformation was evidenced by 1H NMR spectroscopy on peptide 1 in CDCl3. In the NOESY experiment, marked crosspeaks were observed for the NiH-Ni+ 1H resonances in the