Preprotein translocase of the outer mitochondrial membrane:: Molecular dissection and assembly of the general import pore complex
Preprotein translocase of the outer mitochondrial membrane:: Molecular dissection and assembly of the general import pore complex
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DOI：
10.1128/mcb.18.11.6515
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发表时间：
1998-11-01
影响因子：
5.3
通讯作者：
Pfanner, N
中科院分区：
文献类型：
--
作者：
Dekker, PJT;Ryan, MT;Pfanner, N
线粒体外膜前蛋白转位酶（Tom）是一种含有受体和一般输入孔（GIP）的多亚基机制。我们已经分析了汤姆机器的分子结构。受体Tom22与GIP的主要成分Tom40稳定地结合在分子量类似于400，000（类似于400K）的复合物中，而其他受体Tom20和Tom70与该GIP复合物更松散地结合，并且可以在不同的亚复合物中发现。当合成足够量的Tom22时，缺乏Tom20和Tom70的酵母突变体仍然可以形成GIP复合物。除了必需蛋白Tom22和Tom40之外，GIP复合物还包含三个小亚基，Tom5，Tom6和Tom7。在缺少Tom6的突变线粒体中，Tom22和Tom40之间的相互作用不稳定，导致Tom22的解离和含有Tom40、Tom7和Tom5的类似于100K的亚复合物的产生。Tom6需要促进但不维持Tom22和Tom40之间的稳定关联。建议得出以下结论。(i)GIP复合物包含Tom40、Tom22和三个小的Tom蛋白，形成外膜输入机器的中心单元。(ii)Tom20和Tom70对于GIP复合物的产生不是必需的。(iii)Tom6作为Tom22的组装因子，促进其与Tom40的稳定结合。
The preprotein translocase of the outer mitochondrial membrane (Tom) is a multisubunit machinery containing receptors and a general import pore (GIP). We have analyzed the molecular architecture of the Tom machinery. The receptor Tom22 stably associates with Tom40, the main component of the GIP, in a complex with a molecular weight of similar to 400,000 (similar to 400K), while the other receptors, Tom20 and Tom70, are more loosely associated with this GIP complex and can be found in distinct subcomplexes. A yeast mutant lacking both Tom20 and Tom70 can still form the GIP complex when sufficient amounts of Tom22 are synthesized. Besides the essential proteins Tom22 and Tom40, the GIP complex contains three small subunits, Tom5, Tom6, and Tom7. In mutant mitochondria lacking Tom6, the interaction between Tom22 and Tom40 is destabilized, leading to the dissociation of Tom22 and the generation of a subcomplex of similar to 100K containing Tom40, Tom7, and Tom5. Tom6 is required to promote but not to maintain a stable association between Tom22 and Tom40. The following conclusions are suggested. (i) The GIP complex, containing Tom40, Tom22, and three small Tom proteins, forms the central unit of the outer membrane import machinery. (ii) Tom20 and Tom70 are not essential for the generation of the GIP complex. (iii) Tom6 functions as an assembly factor for Tom22, promoting its stable association with Tom40.