start-ver=1.4
cd-journal=joma
no-vol=3
cd-vols=
no-issue=1
article-no=
start-page=232
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2020
dt-pub=20200511
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Structure of a cyanobacterial photosystem I surrounded by octadecameric IsiA antenna proteins
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Iron-stress induced protein A (IsiA) is a chlorophyll-binding membrane-spanning protein in photosynthetic prokaryote cyanobacteria, and is associated with photosystem I (PSI) trimer cores, but its structural and functional significance in light harvesting remains unclear. Here we report a 2.7-angstrom resolution cryo-electron microscopic structure of a supercomplex between PSI core trimer and IsiA from a thermophilic cyanobacterium Thermosynechococcus vulcanus. The structure showed that 18 IsiA subunits form a closed ring surrounding a PSI trimer core. Detailed arrangement of pigments within the supercomplex, as well as molecular interactions between PSI and IsiA and among IsiAs, were resolved. Time-resolved fluorescence spectra of the PSI-IsiA supercomplex showed clear excitation-energy transfer from IsiA to PSI, strongly indicating that IsiA functions as an energy donor, but not an energy quencher, in the supercomplex. These structural and spectroscopic findings provide important insights into the excitation-energy-transfer and subunit assembly mechanisms in the PSI-IsiA supercomplex. Akita et al. present the latest approach to solve IsiA-PSI supercomplex molecular structure with increased resolution using cryo-EM and time-resolved fluorescence studies. With 2.7 angstrom resolution, they reveal molecular interactions between PSI and IsiA subunits and that IsiA functions as an energy donor in the supercomplex.	
en-copyright=
kn-copyright=

en-aut-name=AkitaFusamichi
en-aut-sei=Akita
en-aut-mei=Fusamichi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=NagaoRyo
en-aut-sei=Nagao
en-aut-mei=Ryo
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=KatoKoji
en-aut-sei=Kato
en-aut-mei=Koji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=NakajimaYoshiki
en-aut-sei=Nakajima
en-aut-mei=Yoshiki
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

en-aut-name=YokonoMakio
en-aut-sei=Yokono
en-aut-mei=Makio
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=5
ORCID=

en-aut-name=UenoYoshifumi
en-aut-sei=Ueno
en-aut-mei=Yoshifumi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=6
ORCID=

en-aut-name=SuzukiTakehiro
en-aut-sei=Suzuki
en-aut-mei=Takehiro
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=7
ORCID=

en-aut-name=DohmaeNaoshi
en-aut-sei=Dohmae
en-aut-mei=Naoshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=8
ORCID=

en-aut-name=ShenJian-Ren
en-aut-sei=Shen
en-aut-mei=Jian-Ren
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=9
ORCID=

en-aut-name=AkimotoSeiji
en-aut-sei=Akimoto
en-aut-mei=Seiji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=10
ORCID=

en-aut-name=MiyazakiNaoyuki
en-aut-sei=Miyazaki
en-aut-mei=Naoyuki
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=11
ORCID=

affil-num=1
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Research Institute for Interdisciplinary Science, Okayama University
kn-affil=

affil-num=3
en-affil=Research Institute for Interdisciplinary Science, Okayama University
kn-affil=

affil-num=4
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=5
en-affil=Nippon Flour Mills Co., Ltd., Innovation Center
kn-affil=

affil-num=6
en-affil=Graduate School of Science, Kobe University
kn-affil=

affil-num=7
en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science
kn-affil=

affil-num=8
en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science
kn-affil=

affil-num=9
en-affil= Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=10
en-affil=Graduate School of Science, Kobe University
kn-affil=

affil-num=11
en-affil=Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba
kn-affil=
en-keyword=Cryoelectron microscopy
kn-keyword=Cryoelectron microscopy
en-keyword=Photosystem I
kn-keyword=Photosystem I
END