Structural study of ion-driven energizers by cryo-EM and X-ray crystallography
| Project/Area Number |
16H04757
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural biochemistry
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
Koji Yonekura 国立研究開発法人理化学研究所, 放射光科学研究センター, グループディレクター (50346144)
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| Research Collaborator |
Maki Saori (Yonekura Saori)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥17,550,000 (Direct Cost: ¥13,500,000、Indirect Cost: ¥4,050,000)
Fiscal Year 2018: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
Fiscal Year 2017: ¥7,540,000 (Direct Cost: ¥5,800,000、Indirect Cost: ¥1,740,000)
Fiscal Year 2016: ¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000)
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| Keywords | クライオ電子顕微鏡 / X線結晶構造解析 / 単粒子解析 / 電子線三次元結晶構造解析 / イオンチャネル / プロトン駆動力 / 構造多型 / ダイナミクス / 電荷可視化 / 結晶解析 / イオン駆動力 |
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| Outline of Final Research Achievements |
Gram-negative bacteria import essential nutrients such as iron and vitamin B12 through outer membrane receptors. This process utilizes proton motive force harvested by the Ton system made up of three inner membrane proteins, ExbB, ExbD and TonB. ExbB and ExbD form the proton channel that energizes uptake through TonB. We present structures of hexameric complexes of ExbB and ExbD revealed by X-ray crystallography and single particle cryo-EM. Image analysis shows that hexameric and pentameric complexes coexist, with the proportion of hexamer increasing with pH. Channel current measurement and 2D crystallography support the existence and transition of the two oligomeric states in membranes. The hexameric complex consists of six ExbB subunits and three ExbD transmembrane helices enclosed within the central channel. We propose models for activation / inactivation associated with hexamer and pentamer formation and utilization of proton motive force.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究で、生命の根源的なエネルギーであるプロトン駆動力を利用するExbBDの構造をX線結晶構造解析と単粒子クライオ電子顕微鏡法により決定した。また、これまで知られていなかった膜蛋白質のダイナミックな形態変化という新しい現象の一端が明らかになった。同様の機構は、他の膜蛋白質でも機能の制御などに利用されている可能性も考えられる。このような研究を通じて、実際に薬剤が機能していく段階や過程を可視化することで、新しい創薬技術の創出へと発展することも期待できる。今後、導入した新型クライオ電子顕微鏡を用いて、より高い分解能での単粒子解析と高精度な電子線三次元結晶構造解析を進め、研究を加速したい。
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Report
(4 results)
Research Products
(45 results)
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[Journal Article] Taste substance binding elicits conformational change of taste receptor T1r heterodimer extracellular domains2016
Author(s)
E. Nango, S. Akiyama, S. Maki-Yonekura, Y. Ashikawa, Y. Kusakabe, E. Krayukhina, T. Maruno, S. Uchiyama, N. Nuemket, K. Yonekura, M. Shimizu, N. Atsumi, N. Yasui, T. Hikima, M. Yamamoto, Y. Kobayashi, A. Yamashita
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Journal Title
Sci. Rep
Volume: 6
Issue: 1
Pages: 25745-25745
DOI
Related Report
Peer Reviewed / Open Access
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