光合成複合体間の連係プレイにおける構造基盤の解明

• Project Area: Creation of novel light energy conversion system through elucidation of the molecular mechanism of photosynthesis and its artificial design in terms of time and space
• Project/Area Number: 18H05153
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Research Institution: Ibaraki University
• Principal Investigator: 大友 征宇 茨城大学, 理工学研究科(理学野), 教授 (10213612)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥6,890,000 (Direct Cost: ¥5,300,000、Indirect Cost: ¥1,590,000); Fiscal Year 2019: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2018: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
• Keywords: 光合成 / 電子伝達 / 光電変換

Outline of Annual Research Achievements

本研究は、天然光合成の初期過程における集光・電荷分離と電子移動間の連係プレイ(Interplay)に関するものである。これらの素機能を担う光捕集複合体LH1、反応中心RC、水溶性電子伝達タンパク質HiPIPと膜内チトクロム(Cyt) bc1を研究対象とし、LH1-RC、HiPIPとCyt bc1からなる光捕集・電荷分離・電子伝達の３機能を併せもつ超分子複合体の共結晶化と構造解析を行い、これらの複合体間において機能調節を司る相互作用の構造基盤の解明を目指す。
昨年度HiPIPとLH1-RCの共結晶の形成が確認できたことを受けて、本年度は高分解能を与える共結晶化条件の最適化を行ってきた。HiPIPの割合とpHを細かく変化させて調べた結果、反応中心RCのCサブユニット近傍にHiPIP由来と思われる電子密度が現れた。HiPIP対LH1-RCのモル比の増加に伴い、ある閾値から結晶の回折分解能の低下が見られたことから最適なHiPIP：LH1-RC量論比が存在することがわかった。現在共結晶化条件の最適化を行っているとともに、HiPIPの構造を導入して共結晶の構造モデル構築を開始した。一方、膜タンパク質の性質と複合体の形成に大きな影響を及ぼす膜リン脂質組成について31P-NMRと誘導結合プラズマ蛍光発光（ICP-AES）を用いて同定した。ほとんどの光合成細菌から精製されたLH1-RCにはカルジオリピン（CL）が主成分であることが判明され、膜中でマイナー成分のCLが精製されたLH1-RCに特異的に強く結合していることが示唆された。この成果は国際学術誌（Biochim. Biophys. Acta-Bioenergetics 1860, 461; 2019）に掲載された。

Research Progress Status

令和元年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和元年度が最終年度であるため、記入しない。

Research Products

• [Journal Article] Phospholipid distributions in purple phototrophic bacteria and LH1-RC core complexes (2019)
  • Author(s): Nagatsuma S.、Gotou K.、Yamashita T.、Yu L.-J.、Shen J.-R.、Madigan M.T.、Kimura Y.、Wang-Otomo Z.-Y.
  • Journal Title: Biochimica et Biophysica Acta (BBA) - Bioenergetics Volume: 1860 Issue: 6 Pages: 461-468
  • DOI: 10.1016/j.bbabio.2019.04.001
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A dual role for Ca2+ in expanding the spectral diversity and stability of LH1-RC photocomplexes of purple phototrophic bacteria (2019)
  • Author(s): Imanishi, M., Takenouchi, M., Takaichi, S., Nakagawa, S., Saga, Y., Takenaka, S., Madigan, M.T., vermann, J., Wang-Otomo, Z.-Y., and Kimura Y.
  • Journal Title: Biochemistry Volume: 58 Issue: 25 Pages: 2844-2852
  • DOI: 10.1021/acs.biochem.9b00351
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Blastochloris tepida, sp. nov., a thermophilic species of the bacteriochlorophyll b-containing genus Blastochloris (2019)
  • Author(s): Madigan, M. T, Resnick, S. M., Kempher, M, L., Dolnalkova, A. C., Takaichi, S., Wang-Otomo, Z.-Y., Toyoda, A., Kurokawa, K., Mori, H. and Tsukatani, Y.
  • Journal Title: Arch. Microbiol. Volume: 201 Issue: 10 Pages: 1351-1359
  • DOI: 10.1007/s00203-019-01701-4
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Properties and structure of a low-potential, penta-heme cytochrome c552 from a thermophilic purple sulfur photosynthetic bacterium Thermochromatium tepidum (2019)
  • Author(s): Chen J.-H., Yu L.-J., Boussac A., Wang-Otomo Z.-Y., Kuang T., Shen J.-R.
  • Journal Title: Photosynth. Res. Volume: 139 Issue: 1-3 Pages: 281-293
  • DOI: 10.1007/s11120-018-0507-y
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Structure of photosynthetic LH1-RC supercomplex at 1.9 A resolution (2018)
  • Author(s): Yu Long-Jiang、Suga Michihiro、Wang-Otomo Zheng-Yu、Shen Jian-Ren
  • Journal Title: Nature Volume: 556 Issue: 7700 Pages: 209-213
  • DOI: 10.1038/s41586-018-0002-9
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Biochemical and Spectroscopic Characterizations of a Hybrid Light-Harvesting Reaction Center Core Complex (2018)
  • Author(s): Kimura Yukihiro、Hashimoto Kanako、Akimoto Seiji、Takenouchi Mizuki、Suzuki Kengo、Kishi Rikako、Imanishi Michie、Takenaka Shinji、Madigan Michael T.、Nagashima Kenji V. P.、Wang-Otomo Zheng-Yu
  • Journal Title: Biochemistry Volume: 57 Issue: 30 Pages: 4496-4503
  • DOI: 10.1021/acs.biochem.8b00644
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Novel features of LH1-RC from Thermochromatium tepidum revealed from its atomic resolution structure (2018)
  • Author(s): Yu Long-Jiang、Suga Michihiro、Wang-Otomo Zheng-Yu、Shen Jian-Ren
  • Journal Title: The FEBS Journal Volume: 285 Issue: 23 Pages: 4359-4366
  • DOI: 10.1111/febs.14679
  • Peer Reviewed
• [Journal Article] Cooperative Photoprotection by Multicompositional Carotenoids in the LH1 Antenna from a Mutant Strain of Rhodobacter sphaeroides (2018)
  • Author(s): Yu Jie、Tan Li-Ming、Kawakami Tomoaki、Wang Peng、Fu Li-Min、Wang-Otomo Zheng-Yu、Zhang Jian-Ping
  • Journal Title: The Journal of Physical Chemistry B Volume: 122 Issue: 33 Pages: 8028-8036
  • DOI: 10.1021/acs.jpcb.8b06080
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] New Insights into the Mechanism of Uphill Excitation Energy Transfer from Core Antenna to Reaction Center in Purple Photosynthetic Bacteria (2018)
  • Author(s): Tan Li-Ming、Yu Jie、Kawakami Tomoaki、Kobayashi Masayuki、Wang Peng、Wang-Otomo Zheng-Yu、Zhang Jian-Ping
  • Journal Title: The Journal of Physical Chemistry Letters Volume: 9 Issue: 12 Pages: 3278-3284
  • DOI: 10.1021/acs.jpclett.8b01197
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Orientation assignment of LH2 and LH1-RC complexes from Thermochromatium tepidum reconstituted in PC liposome and their ultrafast excitation dynamics comparison between in artificial and in natural chromatophores (2018)
  • Author(s): Dai Ling、Tan Li-Ming、Jiang Yang-Lin、Shi Ying、Wang Peng、Zhang Jian-Ping、Otomo Zheng-Yu
  • Journal Title: Chemical Physics Letters Volume: 705 Pages: 78-84
  • DOI: 10.1016/j.cplett.2018.05.043
  • Peer Reviewed / Int'l Joint Research
• [Presentation] METAL ION-INDUCED STRUCTURAL AND FUNCTIONAL CHANGES IN BACTERIAL LIGHT-HARVESTING COMPLEXES (2019)
  • Author(s): S. Otomo
  • Organizer: The 3rd International Conference on Solar Fuels (ISF-3), International Conference on Artificial Photosynthesis 2019 (ICARP2019 )
  • Int'l Joint Research / Invited
• [Presentation] Spectroscopic characterization of a bacteriochlorophyll b-based LH1-RC complexes from thermophilic purple bacterium Blactochloris tepida (2019)
  • Author(s): Yukihiro Kimura, Ryuta Seto, Tomoaki Kawakami, Rikako Kishi, Michie Imanishi, Shinichi Takaichi, Shinji Takenaka, Michael T. Madigan, Seiu Otomo
  • Organizer: 第57回日本生物物理学会大会
• [Presentation] A dual role for calcium in expanding the spectral diversity and stability of LH1-RC photocomplexes of purple phototrophic bacteria (2019)
  • Author(s): Michie Imanishi, Mizuki Takenouchi, Shinichi Takaichi, Shiori Nakagawa, Yoshitaka Saga, Shinji Takenaka, Michael T. Madigan, Jorg Overmann, Seiu Otomo and Yukihiro Kimura
  • Organizer: 第57回日本生物物理学会大会
• [Presentation] 好熱性光合成細菌由来のチトクロムbc1複合体、シャペロニン及びリン酸結合タンパク質の単離精製と結晶化 (2019)
  • Author(s): 山下琢也, 川上知朗, 大友征宇
  • Organizer: 日本光合成学会
• [Presentation] Where is the quinone gate in purple photosynthetic bacterial LH1-RC complex? (2018)
  • Author(s): 大友 征宇
  • Organizer: 日本生物物理学会大会
  • Invited
• [Presentation] Origin of the anomalous uphill energy gap in the light-harvesting reaction center from purple photosynthetic bacterium strain 970 (2018)
  • Author(s): 今西三千絵, 小林正幸, 竹中慎治, M. T. Madigan,大友征宇, 木村行宏
  • Organizer: 日本生物物理学会大会
• [Presentation] BChl bをもつ好熱性紅色非硫黄細菌Blastochloris tepida由来LH-RCの特性評価 (2018)
  • Author(s): 川上知朗、鈴木駿平、本田舞、竹之内瑞貴、高市真一、塚谷祐介、木村行宏、M. T. Madigan、大友征宇
  • Organizer: 日本光合成学会
• [Presentation] 963 nmにQy遷移をもつ紅色細菌Thiorhodovibrio strain 970由来LH1-RCの特性評価 (2018)
  • Author(s): 竹之内瑞貴, 川上知朗, 高市真一, 木村行宏, Michael T. Madigan, Jorg Overmann,大友征宇
  • Organizer: 日本光合成学会
• [Remarks] 大友研ホームページ
  • URL: http://biophys.sci.ibaraki.ac.jp