Investigating the SecY plug movement at the SecYEG translocation channel
Investigating the SecY plug movement at the SecYEG translocation channel
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DOI：
10.1038/sj.emboj.7600804
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发表时间：
2005-10-05
期刊：
影响因子：
11.4
通讯作者：
Duong, F
中科院分区：
文献类型：
--
作者：
Tam, PCK;Maillard, AP;Duong, F
蛋白质易位发生在SecYEG通道处的节能细菌膜上。通道的晶体结构揭示了门控和开放的可能机制。本研究使用半胱氨酸交联实验结合各种等位基因形式的Sec复合物来评估塞假说。结果表明，SecY插塞结构域在多肽易位过程中从通道中心向SecE移动，并进一步表明易位增强的prlA3突变和SecG亚基改变了通道门控的性质。将塞子锁定在打开状态预激活Sec复合物，并且当与位于通道孔中的prlA4突变结合时可以产生超活性移位酶。Sec复合物的二聚化，这是易位酶活性所必需的，将塞向开放位置重新定位。我们建议，寡聚化可能会导致SecYEG合作的相互作用重要的总理的易位子功能。
Protein translocation occurs across the energy-conserving bacterial membrane at the SecYEG channel. The crystal structure of the channel has revealed a possible mechanism for gating and opening. This study evaluates the plug hypothesis using cysteine crosslink experiments in combination with various allelic forms of the Sec complex. The results demonstrate that the SecY plug domain moves away from the center of the channel toward SecE during polypeptide translocation, and further show that the translocation-enhancing prlA3 mutation and SecG subunit change the properties of channel gating. Locking the plug in the open state preactivates the Sec complex, and a super-active translocase can be created when combined with the prlA4 mutation located in the pore of the channel. Dimerization of the Sec complex, which is essential for translocase activity, relocates the plug toward the open position. We propose that oligomerization may result in SecYEG cooperative interactions important to prime the translocon function.