Determining the conductance of the SecY protein translocation channel for small molecules
Determining the conductance of the SecY protein translocation channel for small molecules
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DOI：
10.1016/j.molcel.2007.03.022
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发表时间：
2007-05-25
期刊：
影响因子：
16
通讯作者：
Pohl, Peter
中科院分区：
文献类型：
--
作者：
Saparov, Sapar M.;Erlandson, Karl;Pohl, Peter
由SecY复合物形成的通道必须在膜或分泌蛋白的易位期间维持离子和其他小分子的膜屏障。我们已经测试了通道的渗透性，通过使用平面双层含有重组纯化的E。coli SecY复合物。野生型SecY复合物对离子或水不显示任何电导。删除的“塞”，一个短的螺旋通常位于中心的SecY复合物，或修改半胱氨酸引入塞导致短暂的通道开放;类似的效果是看到一个突变的孔环，收缩中心的通道。永久性通道开放时发生的塞被移出的方式由二硫桥的形成。这些数据表明，静止通道本身形成了小分子的屏障，需要孔环和塞子进行密封;通道打开需要塞子的移动。
The channel formed by the SecY complex must maintain the membrane barrier for ions and other small molecules during the translocation of membrane or secretory proteins. We have tested the permeability of the channel by using planar bilayers containing reconstituted purified E. coli SecY complex. Wild-type SecY complex did not show any conductance for ions or water. Deletion of the "plug," a short helix normally located in the center of the SecY complex, or modification of a cysteine introduced into the plug resulted in transient channel openings; a similar effect was seen with a mutation in the pore ring, a constriction in the center of the channel. Permanent channel opening occurred when the plug was moved out of the way by disulfide-bridge formation. These data show that the resting channel on its own forms a barrier for small molecules, with both the pore ring and the plug required for the seal; channel opening requires movement of the plug.