ジャーナル: Nature / 年: 2015 タイトル: Horizontal membrane-intrinsic α-helices in the stator a-subunit of an F-type ATP synthase. 著者: Matteo Allegretti / Niklas Klusch / Deryck J Mills / Janet Vonck / Werner Kühlbrandt / Karen M Davies / 要旨: ATP, the universal energy currency of cells, is produced by F-type ATP synthases, which are ancient, membrane-bound nanomachines. F-type ATP synthases use the energy of a transmembrane ...ATP, the universal energy currency of cells, is produced by F-type ATP synthases, which are ancient, membrane-bound nanomachines. F-type ATP synthases use the energy of a transmembrane electrochemical gradient to generate ATP by rotary catalysis. Protons moving across the membrane drive a rotor ring composed of 8-15 c-subunits. A central stalk transmits the rotation of the c-ring to the catalytic F1 head, where a series of conformational changes results in ATP synthesis. A key unresolved question in this fundamental process is how protons pass through the membrane to drive ATP production. Mitochondrial ATP synthases form V-shaped homodimers in cristae membranes. Here we report the structure of a native and active mitochondrial ATP synthase dimer, determined by single-particle electron cryomicroscopy at 6.2 Å resolution. Our structure shows four long, horizontal membrane-intrinsic α-helices in the a-subunit, arranged in two hairpins at an angle of approximately 70° relative to the c-ring helices. It has been proposed that a strictly conserved membrane-embedded arginine in the a-subunit couples proton translocation to c-ring rotation. A fit of the conserved carboxy-terminal a-subunit sequence places the conserved arginine next to a proton-binding c-subunit glutamate. The map shows a slanting solvent-accessible channel that extends from the mitochondrial matrix to the conserved arginine. Another hydrophilic cavity on the lumenal membrane surface defines a direct route for the protons to an essential histidine-glutamate pair. Our results provide unique new insights into the structure and function of rotary ATP synthases and explain how ATP production is coupled to proton translocation.
EMPIAR-10023 (タイトル: Electron cryo-microscopy of ATP synthase dimers from Polytomella sp. Data size: 4.1 TB Data #1: Multi-frame micrographs (1-24 frames) aligned by motion correction (Li et al 2013) [micrographs - multiframe])
詳細: Quantifoil gold grid with thin carbon support, glow discharged for 2 minutes
凍結
凍結剤: ETHANE / チャンバー内湿度: 75 % / チャンバー内温度: 113 K / 装置: FEI VITROBOT MARK I / 手法: Blot for 8-10 seconds before plunging
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電子顕微鏡法
顕微鏡
FEI POLARA 300
温度
平均: 78 K
アライメント法
Legacy - 非点収差: Objective lens astigmatism was corrected at 155,000 magnification
日付
2014年1月30日
撮影
カテゴリ: CCD フィルム・検出器のモデル: FEI FALCON II (4k x 4k) 実像数: 2829 / 平均電子線量: 80 e/Å2 詳細: Every image is a stack aligned by the motion correction software (Li et al., 2013)