The majority of adenosine triphosphate (ATP) powering cellular processes in eukaryotes is produced by the mitochondrial F1Fo ATP synthase. Here, we present the atomic models of the membrane Fo domain and the entire mammalian (ovine) F1Fo, determined by cryo-electron microscopy. Subunits in the membrane domain are arranged in the ‘proton translocation cluster’ attached to the c-ring and a more distant ‘hook apparatus’ holding subunit e. Unexpectedly, this subunit is anchored to a lipid ‘plug’ capping the c-ring. We present a detailed proton translocation pathway in mammalian Fo and key inter-monomer contacts in F1Fo multimers. Cryo-EM maps of F1Fo exposed to calcium reveal a retracted subunit e and a disassembled c-ring, suggesting permeability transition pore opening. We propose a model for the permeability transition pore opening, whereby subunit e pulls the lipid plug out of the c-ring. Our structure will allow the design of drugs for many emerging applications in medicine.

为真核生物中的细胞过程提供动力的大多数三磷酸腺苷 (ATP) 是由线粒体 F1Fo ATP 合酶产生的。在这里，我们展示了由低温电子显微镜确定的膜 Fo 域和整个哺乳动物（绵羊）F1Fo 的原子模型。膜域中的亚基排列在连接到 c 环的“质子易位簇”和更远的“钩子装置”中，其中包含亚基 e。出乎意料的是，这个亚基锚定在一个脂质“塞子”上，盖住 c 环。我们提出了哺乳动物 Fo 中详细的质子易位途径和 F1Fo 多聚体中的关键单体间接触。暴露于钙的 F1Fo 的冷冻电镜图显示了一个缩回的亚基 e 和一个拆卸的 c 环，表明渗透性过渡孔隙打开。我们提出了渗透率过渡孔隙开口模型，从而亚基 e 将脂质塞拉出 c 环。我们的结构将允许为许多新兴医学应用设计药物。