Department Chemie, Technische Universität München, Lichtenbergstr. 4, Garching, D-85747, Germany.
Department Chemie, Technische Universität München, Lichtenbergstr. 4, Garching, D-85747, Germany.
Biochim Biophys Acta Bioenerg. 2018 Sep;1859(9):734-741. doi: 10.1016/j.bbabio.2018.06.001. Epub 2018 Jun 5.
The respiratory complex I is a redox-driven proton pump that employs the free energy released from quinone reduction to pump protons across its complete ca. 200 Å wide membrane domain. Despite recently resolved structures and molecular simulations, the exact mechanism for the proton transport process remains unclear. Here we combine large-scale molecular simulations with quantum chemical density functional theory (DFT) models to study how contacts between neighboring antiporter-like subunits in the membrane domain of complex I affect the proton transfer energetics. Our combined results suggest that opening of conserved Lys/Glu ion pairs within each antiporter-like subunit modulates the barrier for the lateral proton transfer reactions. Our work provides a mechanistic suggestion for key coupling effects in the long-range force propagation process of complex I.
呼吸复合物 I 是一种氧化还原驱动的质子泵，它利用来自醌还原释放的自由能将质子泵过其完整的约 200 Å 宽的膜域。尽管最近已经解析了结构和分子模拟，但质子传输过程的确切机制仍不清楚。在这里，我们结合了大规模分子模拟和量子化学密度泛函理论 (DFT) 模型来研究膜域中相邻反向转运蛋白样亚基之间的接触如何影响质子转移的能学。我们的综合结果表明，每个反向转运蛋白样亚基内保守的 Lys/Glu 离子对的打开调节了侧向质子转移反应的势垒。我们的工作为复合物 I 长程力传递过程中的关键耦合效应提供了一种机制上的解释。
