start-ver=1.4
cd-journal=joma
no-vol=139
cd-vols=
no-issue=12
article-no=
start-page=4376
end-page=4389
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2017
dt-pub=20170329
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Demonstration of a Light-Driven SO42- Transporter and Its Spectroscopic Characteristics.
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract= 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.
en-copyright=
kn-copyright=

en-aut-name=NihoAkiko
en-aut-sei=Niho
en-aut-mei=Akiko
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=YoshizawaSusumu
en-aut-sei=Yoshizawa
en-aut-mei=Susumu
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=TsukamotoTakashi
en-aut-sei=Tsukamoto
en-aut-mei=Takashi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=KuriharaMarie
en-aut-sei=Kurihara
en-aut-mei=Marie
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

en-aut-name=TaharaShinya
en-aut-sei=Tahara
en-aut-mei=Shinya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=5
ORCID=

en-aut-name=NakajimaYu
en-aut-sei=Nakajima
en-aut-mei=Yu
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=6
ORCID=

en-aut-name=MizunoMisao
en-aut-sei=Mizuno
en-aut-mei=Misao
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=7
ORCID=

en-aut-name=KuramochiHikaru
en-aut-sei=Kuramochi
en-aut-mei=Hikaru
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=8
ORCID=

en-aut-name=TaharaTahei
en-aut-sei=Tahara
en-aut-mei=Tahei
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=9
ORCID=

en-aut-name=MizutaniYasuhisa
en-aut-sei=Mizutani
en-aut-mei=Yasuhisa
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=10
ORCID=

en-aut-name=SudoYuki
en-aut-sei=Sudo
en-aut-mei=Yuki
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=11
ORCID=

affil-num=1
en-affil=Faculty of Pharmaceutical Sciences, Okayama University
kn-affil=

affil-num=2
en-affil=Atmosphere and Ocean Research Institute, The University of Tokyo
kn-affil=

affil-num=3
en-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
kn-affil=

affil-num=4
en-affil= Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
kn-affil=

affil-num=5
en-affil= Molecular Spectroscopy Laboratory, RIKEN
kn-affil=

affil-num=6
en-affil= Atmosphere and Ocean Research Institute, The University of Tokyo
kn-affil=

affil-num=7
en-affil=Department of Chemistry, Graduate School of Science, Osaka University
kn-affil=

affil-num=8
en-affil=Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics
kn-affil=

affil-num=9
en-affil=Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics
kn-affil=

affil-num=10
en-affil=Department of Chemistry, Graduate School of Science, Osaka University
kn-affil=

affil-num=11
en-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
kn-affil=
END