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ID 55198
フルテキストURL
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
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
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.
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.
発行日
2017-03-29
出版物タイトル
Journal of the American Chemical Society
139巻
12号
出版者
American Chemical Society
開始ページ
4376
終了ページ
4389
ISSN
00027863
NCID
AA00692602
資料タイプ
学術雑誌論文
言語
English
OAI-PMH Set
岡山大学
論文のバージョン
author
PubMed ID
DOI
Web of Sience KeyUT
関連URL
isVersionOf https://doi.org/10.1021/jacs.6b12139