线粒体电子传递链的第一个酶，即complex I (NADH:ubiquinone oxidoreductase)，将从NADH 到ubiquinone的电子转移与穿过线粒体内膜的质子转位耦合起来，导致ATP的合成。

 

这篇论文报告了以 5 ?分辨率获得的来自牛心脏线粒体的complex I的电子低温显微镜结构。哺乳动物的这种酶要比以前发表的来自低等生物的complex I的结构大得多。作者确定了44个亚单元中28个的结构——14个保守的(核心)亚单元和14个哺乳动物特有的亚单元。

 

原文摘要：

Architecture of mammalian respiratory complex I

Kutti R. Vinothkumar, Jiapeng Zhu & Judy Hirst

Abstract: Complex I (NADH:ubiquinone oxidoreductase) is essential for oxidative phosphorylation in mammalian mitochondria. It couples electron transfer from NADH to ubiquinone with proton translocation across the energy-transducing inner membrane, providing electrons for respiration and driving ATP synthesis. Mammalian complex I contains 44 different nuclear- and mitochondrial-encoded subunits, with a combined mass of 1 MDa. The 14 conserved ‘core’ subunits have been structurally defined in the minimal, bacterial complex, but the structures and arrangement of the 30 ‘supernumerary’ subunits are unknown. Here we describe a 5 Å resolution structure of complex I from Bos taurus heart mitochondria, a close relative of the human enzyme, determined by single-particle electron cryo-microscopy. We present the structures of the mammalian core subunits that contain eight iron–sulphur clusters and 60 transmembrane helices, identify 18 supernumerary transmembrane helices, and assign and model 14 supernumerary subunits. Thus, we considerably advance knowledge of the structure of mammalian complex I and the architecture of its supernumerary ensemble around the core domains. Our structure provides insights into the roles of the supernumerary subunits in regulation, assembly and homeostasis, and a basis for understanding the effects of mutations that cause a diverse range of human diseases.