Crystal structure and functional characterization of a light-driven chloride pump having an NTQ motif.
Crystal structure and functional characterization of a light-driven chloride pump having an NTQ motif.
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DOI：
10.1038/ncomms12677
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发表时间：
2016-08-24
影响因子：
16.6
通讯作者：
Cho HS
中科院分区：
文献类型：
--
作者：
Kim K;Kwon SK;Jun SH;Cha JS;Kim H;Lee W;Kim JF;Cho HS
在对一种海洋细菌的基因组分析研究中发现了一种新型的光驱动的氯离子泵激视紫红质（ClR），其离子传导途径中含有一个“NTQ基序”。在这里，我们报告的晶体结构的ClR从黄杆菌Nonlabens marinus S1- 08 T在两种条件下确定在2.0和1.56 μ m分辨率。结构揭示了两个氯离子结合位点，一个围绕质子化的席夫碱，另一个在细胞质环上。我们确定了由三个非连续的芳香族氨基酸形成的“3 Ω基序”，与B-C环方向相关。详细的ClR结构分析和E. coli中，揭示了氯离子转导途径。我们的研究结果有助于理解ClR的分子机制和生理作用，并为光遗传学应用提供结构基础。 非典型视紫红质ClR是一种光驱动的氯离子泵蛋白。在这里，作者表明ClR晶体结构呈现两个氯离子结合位点，提出了通过这种光驱动泵进行离子传输的分子途径。
A novel light-driven chloride-pumping rhodopsin (ClR) containing an ‘NTQ motif' in its putative ion conduction pathway has been discovered and functionally characterized in a genomic analysis study of a marine bacterium. Here we report the crystal structure of ClR from the flavobacterium Nonlabens marinus S1-08T determined under two conditions at 2.0 and 1.56 Å resolutions. The structures reveal two chloride-binding sites, one around the protonated Schiff base and the other on a cytoplasmic loop. We identify a ‘3 omega motif' formed by three non-consecutive aromatic amino acids that is correlated with the B–C loop orientation. Detailed ClR structural analyses with functional studies in E. coli reveal the chloride ion transduction pathway. Our results help understand the molecular mechanism and physiological role of ClR and provide a structural basis for optogenetic applications. The atypical rhodopsin ClR from flavobacterium Nonlabens marinus is a light-driven chloride-pumping protein. Here, the authors show that ClR crystal structure presents two chloride ion-binding sites, proposing a molecular pathway for ion transport by this light-driven pump.