Clostridium perfringens Enterotoxin Interacts with Claudins via Electrostatic Attraction
Clostridium perfringens Enterotoxin Interacts with Claudins via Electrostatic Attraction
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DOI：
10.1074/jbc.m109.051417
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发表时间：
2010-01-01
影响因子：
4.8
通讯作者：
Horiguchi, Yasuhiko
中科院分区：
文献类型：
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作者：
Kimura, Jun;Abe, Hiroyuki;Horiguchi, Yasuhiko
产气荚膜梭菌肠毒素(CPE)是一种致孔性毒素，能破坏靶细胞质膜的选择性通透性，导致细胞死亡，是食物中毒的病原。我们先前发现Claudin是CPE的细胞表面受体。Claudin是紧密连接的一个组成部分，是一种四跨膜蛋白，由20多个成员组成，并不是所有的成员都是CPE的受体。这种毒素区分敏感的克劳迪斯的机制尚不清楚。在本研究中，我们将负责与CPE相互作用的claudin区域定位到第二细胞外环的C端部分，发现该区域在敏感的claudins中的等电点高于不敏感的claudins。降低等电点的氨基酸取代导致敏感的Claudins对CPE的敏感性降低，而提高PI的取代使CPE不敏感的Claudins对CPE具有敏感性。CPE的Claudin结合域的空间结构显示出一个酸性裂隙，其周围环绕着Tyr(306)、Tyr(310)、Tyr(312)和Leu(315)，据报道它们是与敏感的Claudins相互作用所必需的。这些结果表明，碱性克拉丁区域和酸性CPE裂隙之间的静电吸引参与了它们的相互作用。
Clostridium perfringens enterotoxin (CPE), a causative agent of food poisoning, is a pore-forming toxin disrupting the selective permeability of the plasma membrane of target cells, resulting in cell death. We previously identified claudin as the cell surface receptor for CPE. Claudin, a component of tight junctions, is a tetratransmembrane protein and constitutes a large family of more than 20 members, not all of which serve as the receptor for CPE. The mechanism by which the toxin distinguishes the sensitive claudins is unknown. In this study, we localized the region of claudin responsible for interaction with CPE to the C-terminal part of the second extracellular loop and found that the isoelectric point of this region in sensitive claudins was higher than insensitive claudins. Amino acid substitutions to lower the pI resulted in reduced sensitivity to CPE among sensitive claudins, whereas substitutions to raise the pI endowed CPE-insensitive claudins with sensitivity. The steric structure of the claudin-binding domain of CPE reveals an acidic cleft surrounded by Tyr(306), Tyr(310), Tyr(312), and Leu(315), which were reported to be essential for interaction with the sensitive claudins. These results imply that an electrostatic attraction between the basic claudin region and the acidic CPE cleft is involved in their interaction.