Structural determinants of lateral gate opening in the protein translocon
Structural determinants of lateral gate opening in the protein translocon
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DOI：
10.1021/bi700835d
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发表时间：
2007-10-02
期刊：
影响因子：
2.9
通讯作者：
Schulten, Klaus
中科院分区：
文献类型：
--
作者：
Gumbart, James;Schulten, Klaus
异源三聚体SecY/Sec 61复合物是一种蛋白传导通道，为蛋白质跨膜提供通道，也是将新生蛋白质整合到膜中的手段。虽然第一种功能在膜蛋白通道和转运蛋白中是常见的，但后者是独特的。新生膜蛋白的插入，一次一个跨膜片段，通过SecY可能通过通道中的侧门发生。分子动力学模拟已被用来研究闸打开的机制。在不同的条件下打开和关闭闸门，使我们能够识别出阻止打开的结构元素以及帮助关闭的结构元素。SecE被认为是保持侧门关闭的夹钳，但没有发挥这种作用。还观察到侧向栅极开口导致的插塞松动，这是沟道选通中的潜在步骤。模拟结果显示，脂质的时间尺度高达1我们不洪水渠道与开放的侧门。
The heterotrimeric SecY/Sec61 complex is a protein-conducting channel that provides a passage for proteins across the membrane as well as a means to integrate nascent proteins into the membrane. While the first function is common among membrane protein channels and transporters, the latter is unique. Insertion of nascent membrane proteins, one transmembrane segment at a time, by SecY likely occurs through a lateral gate in the channel. Molecular dynamics simulations have been used to investigate the mechanism of gate opening. Opening and closing the gate under different conditions allowed us to identify structural elements that resist opening as well as those that aid closure. SecE, considered to act as a clamp keeping the lateral gate closed, was found to play no such role. Loosening of the plug by lateral gate opening, a potential step in channel gating, was also observed. The simulations revealed that lipids on time scales of up to I us do not flood channels with an open lateral gate.