A selective requirement for copper-dependent activation of cytochrome c oxidase by Cox17p
A selective requirement for copper-dependent activation of cytochrome c oxidase by Cox17p
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DOI：
10.1016/j.bbrc.2004.09.211
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发表时间：
2004-11-26
影响因子：
3.1
通讯作者：
Fukamizu, A
中科院分区：
文献类型：
--
作者：
Kako, K;Takehara, A;Fukamizu, A
Cox 17 p是从酵母中克隆的一种分子伴侣，它将铜传递到细胞色素c氧化酶（CCO）组装的线粒体中。在哺乳动物中，CCO是细胞呼吸的关键酶，其功能缺陷与严重的新生儿或婴儿乳酸性酸中毒和早期死亡有关。最近，我们发现Cox 17 p不仅是线粒体氧化磷酸化所必需的，而且对COX 17基因缺陷小鼠的胚胎生长和发育也是必不可少的。为了研究其生化特性，重组人Cox 17 p过表达和纯化，而不纯化标签。在还原条件下，它以3.3 +/- 0.04的铜摩尔含量特异性结合Cu（1），并在体外显著激活线粒体CCO。虽然CuCox 17 p复合物保持在pH值从5.0至7.7之间，但Cu在pH 8.0时从Cox 17 p完全释放。急性暴露过量的铜离子的小鼠细胞导致Cox 17 p mRNA的表达显着减少，而铜饥饿维持Cox 17 p的转录水平。这些结果表明，Cox 17 p对铜的严格选择性是CCO活化所必需的，以防止铜过载，或促进铜的供应。(C)2004年爱思唯尔公司All rights reserved.
Cox17p is cloned from yeast as a chaperone to deliver copper to the mitochondria of assembly for cytochrome c oxidase (CCO). In mammals, CCO is a key enzyme for cellular respiration and a defect in its function is associated with severe neonatal or infantile lactic acidosis and early death. Recently, we found that Cox17p is not only required for mitochondrial oxidative phosphorylation but also is essential for embryonic growth and development in COX1 7 gene-deficient mice. To investigate its biochemical features, recombinant human Cox17p was overexpressed and purified without a purification tag. It specifically binds Cu(1) at a molar copper content of 3.3 +/- 0.04 under reduced conditions and significantly activates the mitochondrial CCO in vitro. Although the CuCox17p complex was maintained between pH values from 5.0 to 7.7, Cu was completely released from Cox17p at pH 8.0. An acute exposure of excess amount of copper ion to mouse cells resulted in a significant reduction of Cox17p mRNA expression, whereas copper starvation maintained the Cox17p transcription level. These results suggest that the stringent selectivity of Cox17p for copper is required for CCO activation to prevent copper overload, or promote the Supply of copper. (C) 2004 Elsevier Inc. All rights reserved.