ID | 55198 |
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著者 |
Niho, Akiko
Faculty of Pharmaceutical Sciences, Okayama University
Yoshizawa, Susumu
Atmosphere and Ocean Research Institute, The University of Tokyo
Tsukamoto, Takashi
Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
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Kurihara, Marie
Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
Tahara, Shinya
Molecular Spectroscopy Laboratory, RIKEN
Nakajima, Yu
Atmosphere and Ocean Research Institute, The University of Tokyo
Mizuno, Misao
Department of Chemistry, Graduate School of Science, Osaka University
Kuramochi, Hikaru
Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics
Tahara, Tahei
Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics
Mizutani, Yasuhisa
Department of Chemistry, Graduate School of Science, Osaka University
Sudo, Yuki
Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
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抄録 | In organisms, ion transporters play essential roles in the generation and dissipation of ion gradients across cell membranes. Microbial rhodopsins selectively transport cognate ions using solar energy, in which the substrate ions identified to date have been confined to monovalent ions such as H+, Na+, and Cl-. Here we report a novel rhodopsin from the cyanobacterium Synechocystis sp. PCC 7509, which inwardly transports a polyatomic divalent sulfate ion, SO42-, with changes of its spectroscopic properties in both unphotolyzed and photolyzed states. Upon illumination, cells expressing the novel rhodopsin, named Synechocystis halorhodopsin (SyHR), showed alkalization of the medium only in the presence of Cl- or SO42-. That alkalization signal was enhanced by addition of a protonophore, indicating an inward transport of Cl- and SO42- with a subsequent secondary inward H+ movement across the membrane. The anion binding to SyHR was suggested by absorption spectral shifts from 542 to 536 nm for Cl- and from 542 to 556 nm for SO42-, and the affinities of Cl- and SO42- were estimated as 0.112 and 5.81 mM, respectively. We then performed time-resolved spectroscopic measurements ranging from femtosecond to millisecond time domains to elucidate the structure and structural changes of SyHR during the photoreaction. Based on the results, we propose a photocycle model for SyHR in the absence or presence of substrate ions with the timing of their uptake and release. Thus, we demonstrate SyHR as the first light-driven polyatomic divalent anion (SO42-) transporter and report its spectroscopic characteristics.
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備考 | This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © American Chemical Society after peer review and technical editing by the publisher.
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発行日 | 2017-03-29
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出版物タイトル |
Journal of the American Chemical Society
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巻 | 139巻
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号 | 12号
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出版者 | American Chemical Society
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開始ページ | 4376
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終了ページ | 4389
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ISSN | 00027863
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NCID | AA00692602
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資料タイプ |
学術雑誌論文
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言語 |
英語
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OAI-PMH Set |
岡山大学
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論文のバージョン | author
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DOI | |
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関連URL | isVersionOf https://doi.org/10.1021/jacs.6b12139
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