Respiratory complex I (NADH:quinone oxidoreductase) plays a central role in generating the proton electrochemical gradient in mitochondrial and bacterial membranes, which is needed to generate ATP. Several high-resolution structures of complex I have been determined, revealing its intricate architecture and complementing the biochemical and biophysical studies. However, the molecular mechanism of long-range coupling between ubiquinone (Q) reduction and proton pumping is not known. Computer simulations have been applied to decipher the dynamics of Q molecule in the ~30 Å long Q tunnel. In this short report, we discuss the binding and dynamics of Q at computationally predicted Q binding sites, many of which are supported by structural data on complex I. We suggest that the binding of Q at these sites is coupled to proton pumping by means of conformational rearrangements in the conserved loops of core subunits.

呼吸复合物I（NADH：醌氧化还原酶）在产生ATP所需的线粒体和细菌膜质子电化学梯度中起着重要作用。已经确定了复合物I的几种高分辨率结构，揭示了其复杂的结构并补充了生物化学和生物物理研究。然而，泛醌（Q）还原和质子泵浦之间的远程耦合的分子机制是未知的。计算机模拟已被用于解密约30Å长Q隧道中Q分子的动力学。在这份简短的报告中，我们讨论了在计算预测的Q结合位点上Q的结合和动力学，其中许多受复杂I的结构数据支持。