CLS

Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology

東京工業大学
科学技術創成研究院
化学生命科学研究所

LAST UPDATE 2022/09/20

  • 研究者氏名
    Researcher Name

    近藤久益子 Kumiko KONDO
    特任助教 Specially-appointed Assistant Professor
  • 所属
    Professional Affiliation

    東京工業大学科学技術創成研究院化学生命科学研究所
    Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology

    分子生命化学部門
    Department of Molecular Bioscience
  • 研究キーワード
    Research Keywords

    光合成
    ATP合成酵素
    シアノバクテリア
    Photosynthesis
    ATP synthase
    Cyanobacteria
研究テーマ
Research Subject
光合成生物特有のATP合成酵素制御メカニズム
The regulation mechanism of ATP synthase unique to photosynthetic organisms

研究の背景 Background

ATP合成酵素は、いわゆるエネルギー産生膜と呼ばれる生体膜に存在し、一般に電子伝達系の働きによりこの膜の内外に形成されるプロトンの電気化学ポテンシャル差(プロトン駆動力)を利用して、ADPと無機リン酸からATPを生産する酵素である。光合成膜に存在するATP合成酵素は、光環境に応じてプロトン駆動力が常に変動し得ることから、特有の制御機構を進化させてきた。

ATP synthase (FoF1) is an enzyme that exists in biological membranes, and produces ATP from ADP and inorganic phosphate by utilizing the electrochemical proton gradient across the membrane. In photosynthetic thylakoid membrane, illumination activates photosynthetic electron transport, generating proton motive force (pmf) across the thylakoid, which drives ATP synthesis. In the dark, FoF1 hydrolyzes ATP as the reverse reaction. Therefore, it is reasonable to assume that these organisms have evolved a unique mechanism for regulating FoF1 activity that utilizes pmf for synthesizing ATP.

研究の目標 Outcome

酸素発生型光合成微生物であるシアノバクテリアを材料に、光合成生物特有の制御メカニズムを明らかにする。また、得られた知見をもとに部位特異的変異を導入することによって、高効率なATP合成酵素の作出を行う。これにより、光合成微生物を用いた物質生産の社会実装への寄与が期待される。

Using cyanobacteria, which are oxygen-evolving photosynthetic bacteria, I will elucidate the regulatory mechanisms unique to phototrophs. I will also create a highly efficient ATP synthase by introducing site-directed mutations. This is expected to contribute to the social implementation of material production using photosynthetic microorganisms.

研究図Research Figure

Fig.1. A schematic diagram of FoF1 ATP synthase from Spinacia oleracea (PDB ID: 6FKF).


Fig.2. Comparison of the γ subunits from various organisms. Upper: The domain architecture of the γ subunit from the phototrophs. They possess a unique insertion sequence within the Rossmann-fold domain, between the N-terminal and C-terminal a helices. Lower: A partial alignment of amino acid sequences around the insertion region. Cyanobacteria and red algae have phototroph-specific insertion, which forms a β-hairpin structure (Hairpin 2). Green plants and green algae have an additional β-hairpin structure (Hairpin 1). We reported that Hairpin 2 critically contributes to its ATP synthesis activity and suppresses ATP hydrolysis.

 

文献 / Publications

Kondo, K., Izumi, M., Inabe, K., Yoshida, K., Imashimizu, M., Suzuki, T., and Hisabori, T., J. Biol. Chem. 475:2925-2939 (2021).
Kondo, K., Takeyama, Y., Sunamura, E.I., Madoka, Y., Fukaya, Y., Isu, A., Hisabori, T., Biochim. Biophys. Acta. 1859:319-325 (2018).