Maximal Efficiency of Coupling between ATP Hydrolysis and Translocation of Polypeptides Mediated by SecB Requires Two Protomers of SecA
Maximal Efficiency of Coupling between ATP Hydrolysis and Translocation of Polypeptides Mediated by SecB Requires Two Protomers of SecA
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DOI：
10.1128/jb.01321-08
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发表时间：
2009-02-01
影响因子：
3.2
通讯作者：
Randall, Linda L.
中科院分区：
文献类型：
--
作者：
Mao, Chunfeng;Hardy, Simon J. S.;Randall, Linda L.
SecA是在蛋白输出期间为前体多肽通过大肠杆菌中的SecYEG易位子易位提供能量的ATP酶。我们以前表明，当SecA接收前体从SecB，三元复合物是完全活跃的，只有当两个protomer SecA的绑定。在这里，我们使用SecA和SecB的变体，填充复合物含有两个Protomer的SecA到不同程度的检查ATP的水解和多肽的易位。我们得出结论，只有一个原聚体的复合物的低活性是ATP之间的耦合效率低的结果;水解和易位。
SecA is the ATPase that provides energy for translocation of precursor polypeptides through the SecYEG translocon in Escherichia coli during protein export. We showed previously that when SecA receives the precursor from SecB, the ternary complex is fully active only when two protomers of SecA are bound. Here we used variants of SecA and of SecB that populate complexes containing two protomers of SecA to different degrees to examine both the hydrolysis of ATP and the translocation of polypeptides. We conclude that the low activity of the complexes with only one protomer is the result of a low efficiency of coupling between ATP ;hydrolysis and translocation.