Structural basis for Na+ transport mechanism by a light-driven Na+ pump
Structural basis for Na+ transport mechanism by a light-driven Na+ pump
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DOI：
10.1038/nature14322
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发表时间：
2015-05-07
期刊：
影响因子：
64.8
通讯作者：
Nureki, Osamu
中科院分区：
文献类型：
--
作者：
Kato, Hideaki E.;Inoue, Keiichi;Nureki, Osamu
Krokinaseikastus rhodopsin 2（KR 2）是第一个发现的光驱动Na+泵，被认为是潜在的下一代光遗传学工具。由于位于所有光驱动离子泵的离子传导路径内的带正电荷的希夫碱质子被认为禁止非质子阳离子的运输，因此KR 2的发现提出了它如何实现Na+运输的问题。在这里，我们目前的晶体结构的KR 2在中性和酸性条件下，这代表休息和M-样的中间状态，分别。结构和光谱分析揭示了门控机制，其中Asp 116的翻转螯合席夫碱质子从传导途径，以促进Na+运输。连同第一个光驱动K1泵的基于结构的工程，哺乳动物神经元的电生理学测定和线虫的行为测定，我们的研究揭示了光驱动非质子阳离子泵的分子基础，从而提供了一个框架，可以推进下一代光遗传学的发展。
Krokinobacter eikastus rhodopsin 2 (KR2) is the first light-driven Na+ pump discovered, and is viewed as a potential next-generation optogenetics tool. Since the positively charged Schiff base proton, located within the ion-conducting pathway of all light-driven ion pumps, was thought to prohibit the transport of a non-proton cation, the discovery of KR2 raised the question of how it achieves Na+ transport. Here we present crystal structures of KR2 under neutral and acidic conditions, which represent the resting and M-like intermediate states, respectively. Structural and spectroscopic analyses revealed the gating mechanism, whereby the flipping of Asp116 sequesters the Schiff base proton from the conducting pathway to facilitate Na+ transport. Together with the structure-based engineering of the first light-driven K1 pumps, electrophysiological assays in mammalian neurons and behavioural assays in a nematode, our studies reveal the molecular basis for light-driven non-proton cation pumps and thus provide a framework that may advance the development of next-generation optogenetics.