Conformational alterations in unidirectional ion transport of a light-driven chloride pump revealed using X-ray free electron lasers.
Conformational alterations in unidirectional ion transport of a light-driven chloride pump revealed using X-ray free electron lasers.
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DOI：
10.1073/pnas.2117433119
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发表时间：
2022-03-01
影响因子：
11.1
通讯作者：
Shirouzu M
中科院分区：
文献类型：
--
作者：
Hosaka T;Nomura T;Kubo M;Nakane T;Fangjia L;Sekine SI;Ito T;Murayama K;Ihara K;Ehara H;Kashiwagi K;Katsura K;Akasaka R;Hisano T;Tanaka T;Tanaka R;Arima T;Yamashita A;Sugahara M;Naitow H;Matsuura Y;Yoshizawa S;Tono K;Owada S;Nureki O;Kimura-Someya T;Iwata S;Nango E;Shirouzu M
光驱动的氯化物泵已经在各种物种中被发现，包括古细菌和海洋黄杆菌。光控制离子运输的功能被用于神经科学中的光遗传学工具。氯化物泵在氨基酸同源性和结构相似性方面因物种而异。我们利用x射线自由电子激光进行了时间分辨晶体学研究，揭示了海洋黄杆菌中卤化物离子在光驱动氯化物泵中转移的分子机制。与之前氯离子泵的低温捕获研究相比，我们的数据表明了氯离子泵视紫红质的共同机制。这些发现不仅对进一步改进光遗传学工具，而且对微生物视紫红质离子泵送机制的一般理解具有重要意义。光驱动氯化物泵送视紫红质主动运输阴离子，包括各种卤化物离子，跨细胞膜。近年来，利用时间分辨连续飞秒晶体学（TR-SFX）的研究揭示了光驱动阳离子泵送视紫红质的结构变化和离子转移机制。然而，阴离子泵送紫红质中的构象变化泵送阴离子以实现从胞外侧到胞质侧的单向离子运输的机制仍然是谜。我们收集了来自海洋黄杆菌的Nonlabens marinus rhodopsin-3 （NM-R3）在光激发后10µs和1 ms时间点的TR-SFX数据。我们的结构分析揭示了离子转移期间和离子释放后的构象变化。视网膜发色团的运动最初将保守的色氨酸转移到NM-R3的细胞质侧，同时伴随着与视网膜结合的卤化物离子的轻微移动。离子释放后，螺旋C和螺旋G的向内运动以及视网膜的侧向位移阻断了NM-R3细胞外侧的通路。从含有碘离子的纳米- r3晶体中也获得了异常信号数据。异常密度图提供了对纳米- r3中离子转移的卤化物结合位点的深入了解。
Light-driven chloride pumps have been identified in various species, including archaea and marine flavobacteria. The function of ion transportation controllable by light is utilized for optogenetics tools in neuroscience. Chloride pumps differ among species, in terms of amino acid homology and structural similarity. Our time-resolved crystallographic studies using X-ray free electron lasers reveal the molecular mechanism of halide ion transfer in a light-driven chloride pump from a marine flavobacterium. Our data indicate a common mechanism in chloride pumping rhodopsins, as compared to previous low-temperature trapping studies of chloride pumps. These findings are significant not only for further improvements of optogenetic tools but also for a general understanding of the ion pumping mechanisms of microbial rhodopsins. Light-driven chloride-pumping rhodopsins actively transport anions, including various halide ions, across cell membranes. Recent studies using time-resolved serial femtosecond crystallography (TR-SFX) have uncovered the structural changes and ion transfer mechanisms in light-driven cation-pumping rhodopsins. However, the mechanism by which the conformational changes pump an anion to achieve unidirectional ion transport, from the extracellular side to the cytoplasmic side, in anion-pumping rhodopsins remains enigmatic. We have collected TR-SFX data of Nonlabens marinus rhodopsin-3 (NM-R3), derived from a marine flavobacterium, at 10-µs and 1-ms time points after photoexcitation. Our structural analysis reveals the conformational alterations during ion transfer and after ion release. Movements of the retinal chromophore initially displace a conserved tryptophan to the cytoplasmic side of NM-R3, accompanied by a slight shift of the halide ion bound to the retinal. After ion release, the inward movements of helix C and helix G and the lateral displacements of the retinal block access to the extracellular side of NM-R3. Anomalous signal data have also been obtained from NM-R3 crystals containing iodide ions. The anomalous density maps provide insight into the halide binding site for ion transfer in NM-R3.
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影响因子：
62.1
作者：
Ernst, Oliver P.;Lodowski, David T.;Elstner, Marcus;Hegemann, Peter;Brown, Leonid S.;Kandori, Hideki
通讯作者：
Kandori, Hideki
影响因子：
16.6
作者：
Govorunova EG;Sineshchekov OA;Li H;Spudich JL
通讯作者：
Spudich JL
影响因子：
2.9
作者：
Dioumaev, AK;Wang, JM;Lanyi, JK
通讯作者：
Lanyi, JK
影响因子：
16.6
作者：
Kim K;Kwon SK;Jun SH;Cha JS;Kim H;Lee W;Kim JF;Cho HS
通讯作者：
Cho HS
影响因子：
3.3
作者：
Gmelin, Walter;Zeth, Kornelius;Oesterhelt, Dieter
通讯作者：
Oesterhelt, Dieter