Mitochondrial cytochrome c oxidase (CcO) or respiratory chain complex IV is a heme aa₃-copper oxygen reductase containing metal centers essential for holo-complex biogenesis and enzymatic function that are assembled by subunit-specific metallochaperones. The enzyme has two copper sites located in the catalytic core subunits. The COX1 subunit harbors the Cu_B site that tightly associates with heme a₃ while the COX2 subunit contains the binuclear Cu_A site. Here, we report that in human cells the CcO copper chaperones form macromolecular assemblies and cooperate with several twin CX₉C proteins to control heme a biosynthesis and coordinate copper transfer sequentially to the Cu_A and Cu_B sites. These data on CcO illustrate a mechanism that regulates the biogenesis of macromolecular enzymatic assemblies with several catalytic metal redox centers and prevents the accumulation of cytotoxic reactive assembly intermediates.

线粒体细胞色素c氧化酶 (CcO) 或呼吸链复合物 IV 是一种血红素aa ₃ -铜氧还原酶，含有对全复合物生物发生和酶功能至关重要的金属中心，由亚基特异性金属伴侣组装而成。该酶在催化核心亚基上有两个铜位点。 COX1 亚基含有与血红素a ₃紧密结合的 Cu _B位点，而 COX2 亚基含有双核 Cu _A位点。在这里，我们报告在人类细胞中，CcO 铜伴侣形成大分子组装体，并与几个孪生 CX ₉ C 蛋白配合控制血红素a生物合成并协调铜顺序转移到 Cu _A和 Cu _B位点。这些关于 CcO 的数据说明了一种调节具有多个催化金属氧化还原中心的大分子酶组装体的生物发生并防止细胞毒性反应组装中间体积累的机制。