An Electron-Transfer Path through an Extended Disulfide Relay System: The Case of the Redox Protein ALR
An Electron-Transfer Path through an Extended Disulfide Relay System: The Case of the Redox Protein ALR
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DOI：
10.1021/ja209881f
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发表时间：
2012-01-25
影响因子：
15
通讯作者：
Tokatlidis, Kostas
中科院分区：
文献类型：
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作者：
Banci, Lucia;Bertini, Ivano;Tokatlidis, Kostas
人线粒体膜间空间的氧化折叠机制支持由进口受体Mia40和同源二聚体fad依赖的硫醇氧化酶ALR组成的二硫传递系统。黄素蛋白ALR从Mia40每个亚基接收两个电子，然后通过单电子反应将这些电子提供给两个细胞色素c分子，从而介导从双电子到单电子的转移。我们在这里解剖了ALR内的电子通量机制，在原子水平上表征了允许电子快速流向细胞色素c的ALR中间体。电子转移过程的关键中间体意味着形成特定的亚基间二硫化物，该亚基间二硫化物只允许电子从Mia40流向FAD。这一发现使我们能够为ALR中的电子转移途径提供一个完整的模型
The oxidative folding mechanism in the intermembrane space of human mitochondria underpins a disulfide relay system consisting of the import receptor Mia40 and the homodimeric FAD-dependent thiol oxidase ALR. The flavoprotein ALR receives two electrons per subunit from Mia40, which are then donated through one-electron reactions to two cytochrome c molecules, thus mediating a switch from two-electron to one-electron transfer. We dissect here the mechanism of the electron flux within ALR, characterizing at the atomic level the ALR intermediates that allow electrons to rapidly flow to cytochrome c. The intermediate critical for the electron-transfer process implies the formation of a specific inter-subunit disulfide which exclusively allows electron flow from Mia40 to FAD. This finding allows us to present a complete model for the electron-transfer pathway in ALR