A role for cytochrome c and cytochrome c peroxidase in electron shuttling from Erv1
A role for cytochrome c and cytochrome c peroxidase in electron shuttling from Erv1
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DOI：
10.1038/sj.emboj.7601909
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发表时间：
2007-11-01
期刊：
影响因子：
11.4
通讯作者：
Koehler, Carla M.
中科院分区：
文献类型：
--
作者：
Dabir, Deepa V.;Leverich, Edward P.;Koehler, Carla M.
Erv 1是线粒体膜间隙（IMS）中的黄素依赖性巯基氧化酶，其在富含半胱氨酸的蛋白质的输入中起作用。重组Erv 1的氧化还原滴定表明，它包含三个不同的对，中点电位为-320，-215，和-150 mV。像所有氧化还原活性酶一样，Erv 1需要一个或多个电子受体。我们已经产生了菌株与erv 1条件等位基因，并采用生化和遗传策略，以促进识别涉及Erv 1的氧化还原途径。在这里，我们报告说，Erv 1与细胞色素c形成1：1的复合物，还原Erv 1可以直接将电子转移到细胞色素的铁形式。Erv 1还利用分子氧作为电子受体产生过氧化氢，随后通过细胞色素c过氧化物酶（Ccp 1）将其还原为水。氧化的Ccp 1又被Erv 1还原的细胞色素c还原。通过耦合这些途径，细胞色素c和Ccp 1有效地作为Erv 1依赖的电子受体。因此，我们建议，Erv 1利用不同的途径在IMS中的电子穿梭。
Erv1 is a flavin-dependent sulfhydryl oxidase in the mitochondrial intermembrane space (IMS) that functions in the import of cysteine- rich proteins. Redox titrations of recombinant Erv1 showed that it contains three distinct couples with midpoint potentials of -320, -215, and -150mV. Like all redox- active enzymes, Erv1 requires one or more electron acceptors. We have generated strains with erv1 conditional alleles and employed biochemical and genetic strategies to facilitate identifying redox pathways involving Erv1. Here, we report that Erv1 forms a 1: 1 complex with cytochrome c and a reduced Erv1 can transfer electrons directly to the ferric form of the cytochrome. Erv1 also utilized molecular oxygen as an electron acceptor to generate hydrogen peroxide, which is subsequently reduced to water by cytochrome c peroxidase (Ccp1). Oxidized Ccp1 was in turn reduced by the Erv1-reduced cytochrome c. By coupling these pathways, cytochrome c and Ccp1 function efficiently as Erv1- dependent electron acceptors. Thus, we propose that Erv1 utilizes diverse pathways for electron shuttling in the IMS.