フルテキストURL J. Biol. Chem_292_23_9599.pdf
著者 Motomura, Taiki| Suga, Michihiro| Hienerwadel, Rainer| Nakagawa, Akiko| Lai, Thanh-Lan| Nitschke, Wolfgang| Kuma, Takahiro| Sugiura, Miwa| Boussac, Alain| Shen, Jian-Ren|
抄録 Photosystem II catalyzes light-induced water oxidation leading to the generation of dioxygen indispensable for sustaining aerobic life on Earth. The Photosystem II reaction center is composed of D1 and D2 proteins encoded by psbA and psbD genes, respectively. In cyanobacteria, different psbA genes are present in the genome. The thermophilic cyanobacterium Thermosynechococcus elongatus contains three psbA genes: psbA1, psbA2, and psbA3, and a new c-type heme protein, Tll0287, was found to be expressed in a strain expressing the psbA2 gene only, but the structure and function of Tll0287 are unknown. Here we solved the crystal structure of Tll0287 at a 2.0 Å resolution. The overall structure of Tll0287 was found to be similar to some kinases and sensor proteins with a Per-Arnt-Sim-like domain rather than to other c-type cytochromes. The fifth and sixth axial ligands for the heme were Cys and His, instead of the His/Met or His/His ligand pairs observed for most of the c-type hemes. The redox potential, E½, of Tll0287 was -255 ± 20 mV versus normal hydrogen electrode at pH values above 7.5. Below this pH value, the E½ increased by ≈57 mV/pH unit at 15 °C, suggesting the involvement of a protonatable group with a pKred = 7.2 ± 0.3. Possible functions of Tll0287 as a redox sensor under microaerobic conditions or a cytochrome subunit of an H2S-oxidizing system are discussed in view of the environmental conditions in which psbA2 is expressed, as well as phylogenetic analysis, structural, and sequence homologies.
キーワード D1 protein His-Cys heme axial coordination PAS domain PAS-like domain Tll0287 X-ray crystallography cytochrome heme photosynthesis photosystem II
発行日 2017-06
出版物タイトル Journal of Biological Chemistry
292巻
23号
出版者 American Society for Biochemistry and Molecular Biology
開始ページ 9599
終了ページ 9612
ISSN 0021-9258
NCID AA00251083
資料タイプ 学術雑誌論文
言語 English
OAI-PMH Set 岡山大学
著作権者 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja
論文のバージョン publisher
PubMed ID 28428249
DOI 10.1074/jbc.M116.746263
Web of Sience KeyUT 000403113000012
関連URL isVersionOf https://doi.org/10.1074/jbc.M116.746263
フルテキストURL CurrOpinStructBiol_39_46.pdf
著者 菅 倫寛| Qin, Xiaochun| Kuang, Tingyun| 沈 建仁|
抄録 Photosystem I (PSI) is one of the two photosystems in oxygenic photosynthesis, and absorbs light energy to generate reducing power for the reduction of NADP+ to NADPH with a quantum efficiency close to 100%. The plant PSI core forms a supercomplex with light-harvesting complex I (LHCI) with a total molecular weight of over 600 kDa. Recent X-ray structure analysis of the PSI-LHCI membrane-protein supercomplex has revealed detailed arrangement of the light-harvesting pigments and other cofactors especially within LHCI. Here we introduce the overall structure of the PSI-LHCI supercomplex, and then focus on the excited energy transfer (EET) pathways from LHCI to the PSI core and photoprotection mechanisms based on the structure obtained.
備考 © 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
発行日 2016-08
出版物タイトル Current Opinion in Structural Biology
39巻
出版者 CURRENT BIOLOGY LTD
開始ページ 46
終了ページ 53
ISSN 0959-440X
NCID AA10836185
資料タイプ 学術雑誌論文
言語 English
OAI-PMH Set 岡山大学
著作権者 http://creativecommons.org/licenses/by-nc-nd/4.0/
論文のバージョン author
PubMed ID 27131043
DOI 10.1016/j.sbi.2016.04.004
Web of Sience KeyUT 000386411000008
関連URL https://doi.org/10.1016/j.sbi.2016.04.004