Department of Biochemistry II, University of Göttingen, D-37073 Göttingen, Germany.
Cell Metab. 2012 Mar 7;15(3):336-47. doi: 10.1016/j.cmet.2012.01.016. Epub 2012 Feb 16.
The terminal enzyme of the mitochondrial respiratory chain, cytochrome oxidase, transfers electrons to molecular oxygen, generating water. Within the inner mitochondrial membrane, cytochrome oxidase assembles into supercomplexes, together with other respiratory chain complexes, forming so-called respirasomes. Little is known about how these higher oligomeric structures are attained. Here we report on Rcf1 and Rcf2 as cytochrome oxidase subunits in S. cerevisiae. While Rcf2 is specific to yeast, Rcf1 is a conserved subunit with two human orthologs, RCF1a and RCF1b. Rcf1 is required for growth in hypoxia and complex assembly of subunits Cox13 and Rcf2, as well as for the oligomerization of a subclass of cytochrome oxidase complexes into respirasomes. Our analyses reveal that the cytochrome oxidase of mitochondria displays intrinsic heterogeneity with regard to its subunit composition and that distinct forms of respirasomes can be formed by complex variants.
线粒体呼吸链的末端酶——细胞色素氧化酶将电子传递给分子氧，生成水。在 线粒体内膜中，细胞色素氧化酶与其他呼吸链复合物一起组装成超复合物，形成所谓的呼吸体。关于这些更高的寡聚结构是如何形成的，人们知之甚少。在这里，我们报道了 S. cerevisiae 中的细胞色素氧化酶亚基 Rcf1 和 Rcf2。虽然 Rcf2 是酵母特有的，但 Rcf1 是一个保守的亚基，有两个人类同源物，RCF1a 和 RCF1b。Rcf1 对于低氧生长和亚基 Cox13 和 Rcf2 的复合物组装以及亚类细胞色素氧化酶复合物的寡聚化形成呼吸体是必需的。我们的分析表明，线粒体的细胞色素氧化酶在其亚基组成方面表现出固有异质性，并且可以通过复合物变体形成不同形式的呼吸体。
