在这里，研究人员将时间分辨系列晶体学与时间分辨光谱学和多尺度模拟相结合，以阐明氯离子泵送视紫红质的分子机制和整个运输周期的结构动力学。他们追踪了瞬时阴离子结合位点，获得了光能如何用于泵送机制的证据，并确定了确保单向传输的空间和静电分子门。与视网膜的π-电子系统的相互作用支持瞬时氯离子的结合，跨越运输途径的一个主要瓶颈。这些结果使我们能够提出关键的机制特征，使这种光动力氯离子泵能够精细地控制氯离子在细胞膜上的转运。
据介绍，微生物视紫红质的氯化物转运是一个必不可少的过程，其分子细节（例如将光能转化为驱动离子泵浦和确保转运单向性的机制）仍然难以捉摸。
附：英文原文
Title: Dynamics and mechanism of a light-driven chloride pump
Author: Sandra Mous, Guillaume Gotthard, David Ehrenberg, Saumik Sen, Tobias Weinert, Philip J. M. Johnson, Daniel James, Karol Nass, Antonia Furrer, Demet Kekilli, Pikyee Ma, Steffen Brünle, Cecilia Maria Casadei, Isabelle Martiel, Florian Dworkowski, Dardan Gashi, Petr Skopintsev, Maximilian Wranik, Gregor Knopp, Ezequiel Panepucci, Valerie Panneels, Claudio Cirelli, Dmitry Ozerov, Gebhard F. X. Schertler, Meitian Wang, Chris Milne, Joerg Standfuss, Igor Schapiro, Joachim Heberle, Przemyslaw Nogly
Issue&Volume: 2022-02-03
Abstract: Chloride transport by microbial rhodopsins is an essential process for which molecular details such as the mechanisms that convert light energy to drive ion pumping and ensure the unidirectionality of the transport have remained elusive. We combined time-resolved serial crystallography with time-resolved spectroscopy and multiscale simulations to elucidate the molecular mechanism of a chloride-pumping rhodopsin and the structural dynamics throughout the transport cycle. We traced transient anion-binding sites, obtained evidence for how light energy is used in the pumping mechanism, and identified steric and electrostatic molecular gates ensuring unidirectional transport. An interaction with the π-electron system of the retinal supports transient chloride ion binding across a major bottleneck in the transport pathway. These results allow us to propose key mechanistic features enabling finely controlled chloride transport across the cell membrane in this light-powered chloride ion pump.
DOI: abj6663
Source: https://www.science.org/doi/10.1126/science.abj6663