Quaternary structure of the mitochondrial TIM23 complex reveals dynamic association between Tim23p and other subunits
Quaternary structure of the mitochondrial TIM23 complex reveals dynamic association between Tim23p and other subunits
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DOI：
10.1091/mbc.e07-07-0669
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发表时间：
2008-01-01
影响因子：
3.3
通讯作者：
Johnson, Arthur E.
中科院分区：
文献类型：
--
作者：
Alder, Nathan N.;Sutherland, Jennifer;Johnson, Arthur E.
Tim 23 p是线粒体内膜的多亚基TIM 23复合物的重要通道形成组分，其介导蛋白质输入。在体外导入放射性标记的Tim 23 p单半胱氨酸突变体，掺入功能性TIM 23复合物中，并进行化学交联。Tim 23 p和其他TIM 23复合物亚基之间的三个邻近区域被鉴定：Tim 17 p和Tim 23 p的第一个跨膜片段; Tim 50 p和Tim 23 p亲水区域的C-末端;以及Tim 23 p分子的整个亲水结构域。这些邻近区域响应于跨内膜的膜电位的变化而可逆地变化，并且当易位底物被困在TIM 23复合物中时也是如此。这些结构变化揭示了TIM 23复合物内的大分子排列是动态的，并且随着细胞的生理状态而变化。
Tim23p is an essential channel-forming component of the multisubunit TIM23 complex of the mitochondrial inner membrane that mediates protein import. Radiolabeled Tim23p monocysteine mutants were imported in vitro, incorporated into functional TIM23 complexes, and subjected to chemical cross-linking. Three regions of proximity between Tim23p and other subunits of the TIM23 complex were identified: Tim17p and the first transmembrane segment of Tim23p; Tim50p and the C-terminal end of the Tim23p hydrophilic region; and the entire hydrophilic domains of Tim23p molecules. These regions of proximity reversibly change in response to changes in membrane potential across the inner membrane and also when a translocating substrate is trapped in the TIM23 complex. These structural changes reveal that the macromolecular arrangement within the TIM23 complex is dynamic and varies with the physiological state of the mitochondrion.