The solution structure of horseshoe crab antimicrobial peptide tachystatin B with an inhibitory cystine-knot motif
The solution structure of horseshoe crab antimicrobial peptide tachystatin B with an inhibitory cystine-knot motif
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DOI：
10.1002/psc.846
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发表时间：
2007-04-01
影响因子：
2.1
通讯作者：
Kawano, Keiichi
中科院分区：
文献类型：
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作者：
Fujitani, Naoki;Kouno, Takahide;Kawano, Keiichi
Tachystatin B 是一种抗菌剂，是一种从日本鲎 (Tachypleus tridentatus) 中分离出来的几丁质结合肽，由两种称为 tachystatin B1 和 B2 的异肽组成。我们使用核磁共振实验和距离几何计算确定了它们的溶液结构。对于 Cys(4)-Arg(40) 中的主链原子，速抑素 B1 和 B2 的 20 个最佳收敛结构分别表现出 0.46 和 0.49 埃的均方根偏差。两种结构具有相同的构象，并且它们包含一个短的反平行 β 片层，其具有抑制性胱氨酸结 (ICK) 基序，该基序广泛分布在电压门控离子通道的拮抗剂中，尽管速抑素 B 不具有神经毒性活性。结构同源性搜索提供了几种与速他汀B结构相似的肽，但大多数都具有杀虫活性等高级功能，这表明速他汀B可能是分子进化史上抗菌肽的祖先。速他汀 B 还表现出与速他汀 A 的显着结构相似性，后者是速他汀家族的成员。两种速抑素的结构比较表明，第一链和第二链之间的长环中的Tyr(14)和Arg(17)可能是与几丁质结合的必需残基。版权所有 (C) 2007 欧洲肽协会和 John Wiley & Sons, Ltd.
Tachystatin B is an antimicrobial and a chitin-binding peptide isolated from the Japanese horseshoe crab (Tachypleus tridentatus) consisting of two isopeptides called tachystatin B1 and B2. We have determined their solution structures using NMR experiments and distance geometry calculations. The 20 best converged structures of tachystatin B1 and B2 exhibited root mean square deviations of 0.46 and 0.49 angstrom, respectively, for the backbone atoms in Cys(4)-Arg(40). Both structures have identical conformations, and they contain a short antiparallel beta-sheet with an inhibitory cystine-knot (ICK) motif that is distributed widely in the antagonists for voltage-gated ion channels, although tachystatin B does not have neurotoxic activity. The structural homology search provided several peptides with structures similar to that of tachystatin B. However, most of them have the advanced functions such as insecticidal activity, suggesting that tachystatin B may be a kind of ancestor of antimicrobial peptide in the molecular evolutionary history. Tachystatin B also displays a significant structural similarity to tachystatin A, which is member of the tachystatin family. The structural comparison of both tachystatins indicated that Tyr(14) and Arg(17) in the long loop between the first and second strands might be the essential residues for binding to chitin. Copyright (C) 2007 European Peptide Society and John Wiley & Sons, Ltd.