AbstractCell membranes, despite providing a barrier to protect intracellular constituents, require selective gating for the influx of important metabolites including ions, sugars, amino acids, neurotransmitters and efflux of toxins and metabolic end-products. The machinery involved in carrying out this gating process comprises of integral membrane proteins that use ionic electrochemical gradients or ATP hydrolysis, to drive concentrative uptake or efflux. The mechanism through which ion-coupled transporters function is referred to as alternating-access. In the recent past, discrete modes of alternating-access have been described with the elucidation of new transporter structures and their snapshots in altered conformational states. Despite X-ray structures being the primary sources of mechanistic information, other biophysical methods provide information related to the structural dynamics of these transporters. Methods including EPR and smFRET, have extensively helped validate or clarify ion-coupled transport mechanisms, in a near-native environment. This review seeks to highlight the mechanistic details of ion-coupled transport and delve into the biophysical tools and methods that help in understanding these fascinating molecules.

中文翻译：

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透过窥镜的转运体：对离子耦合转运机制和有助于揭示它们的方法的洞察

摘要细胞膜尽管提供了保护细胞内成分的屏障，但仍需要对重要代谢物的流入进行选择性门控，包括离子、糖、氨基酸、神经递质以及毒素和代谢终产物的流出。执行此门控过程所涉及的机制包括使用离子电化学梯度或 ATP 水解来驱动集中吸收或流出的完整膜蛋白。离子耦合转运蛋白发挥作用的机制称为交替访问。在最近的过去，已经描述了交替访问的离散模式，阐明了新的转运蛋白结构及其在改变构象状态下的快照。尽管 X 射线结构是机械信息的主要来源，其他生物物理方法提供了与这些转运蛋白的结构动力学相关的信息。包括 EPR 和 smFRET 在内的方法在近乎原生的环境中广泛地帮助验证或阐明了离子耦合传输机制。这篇综述旨在强调离子耦合传输的机制细节，并深入研究有助于理解这些迷人分子的生物物理工具和方法。