Different regions of the nonconserved large periplasmic domain of Escherichia coli YidC are involved in the SecF interaction and membrane insertase activity
Different regions of the nonconserved large periplasmic domain of Escherichia coli YidC are involved in the SecF interaction and membrane insertase activity
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DOI：
10.1021/bi060826z
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发表时间：
2006-11-07
期刊：
影响因子：
2.9
通讯作者：
Kuhn, Andreas
中科院分区：
文献类型：
--
作者：
Xie, Kun;Kiefer, Dorothee;Kuhn, Andreas
大肠杆菌的YidC蛋白是插入Sec-非依赖性膜蛋白所必需的，并且对于Sec-依赖性蛋白插入膜双层中具有支持作用。由于YidC的一部分与Sec易位酶共纯化，这种相互作用可能是必要的，以协助Sec依赖性蛋白质的膜插入。本研究描述了一种缺失分析，调查YidC的哪些部分是必需的，其相互作用与SecDF复合物的SEC易位酶和YidC的功能作为一个插入酶的SEC依赖性膜蛋白。结果表明，包括残基24-346的第一周质区域是YidC与Sec易位酶，特别是与SecF蛋白相互作用所需的。进一步的研究表明，YidC的残基215-265足以与SecF结合。令人惊讶的是，YidC与SecF的相互作用对于细胞活力不是关键的，因为缺少残基24-264的YidC完全具有支持大肠杆菌生长的功能。杆菌还观察到该YidC突变体具有插入F1 Fo ATP合酶的Sec依赖性亚基A和M13前外壳衍生物以及Sec非依赖性M13前外壳蛋白和ATP合酶的亚基C的完全功能。只有当周质区域的额外残基被删除时（265-346），YidC的膜插入酶功能才被抑制。
The YidC protein of Escherichia coli is required for inserting Sec-independent membrane proteins and has a supportive role for the insertion of Sec-dependent proteins into the membrane bilayer. Because a portion of YidC copurifies with the Sec translocase, this interaction might be necessary to assist in the membrane insertion of Sec-dependent proteins. This study describes a deletion analysis that investigates which parts of YidC are required for its interaction with the SecDF complex of the Sec translocase and for the function of YidC as an insertase for the Sec-dependent membrane proteins. The results suggest that the first periplasmic region, which includes residues 24-346, is required for the interaction of YidC with the Sec translocase, in particular with the SecF protein. Further studies showed that residues 215-265 of YidC are sufficient for SecF binding. Surprisingly, the interaction of YidC with SecF is not critical for cell viability as YidC, lacking residues 24-264, was fully functional to support the growth of E. coli. It was also observed that this YidC mutant was fully functional to insert the Sec-dependent subunit A of the F1Fo ATP synthase and an M13 procoat derivative, as well as the Sec-independent M13 procoat protein and subunit C of the ATP synthase. Only when additional residues of the periplasmic region were deleted (265-346) was the membrane insertase function of YidC inhibited.