Investigation of ion-pumping rhodopsins with a high-time resolution

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K06109
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 43030:Functional biochemistry-related
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: Tsunoda Satoshi 名古屋工業大学, 工学(系)研究科(研究院), 研究員 (00598857)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: ロドプシン / 電気生理学 / 光遺伝学 / イオンポンプ / 光受容体 / イオンチャネル

Outline of Final Research Achievements

Ion transport properties of various microbial rhodopsin were investigated under a high-time resolved condition by combining electrophysiology with a flash laser. Single turnover reaction of sodium ion transport by KR2, a sodium pumping rhodopsin was recorded. Kinetical analysis revealed that the turnover rate was 10 times faster than reported value obtained under multiple turnover conditions, suggesting two distinct reaction pathways in the KR2 photocycle.
Moreover, ion transport of 9 different proton pumping rhodopsins were systematically tested in conventional patch-clamp recording. The pumping activity of those are pH- and membrane-voltage dependent. Data revealed that the pH at the proton exclusion side largely affect the proton transport.

Free Research Field

生物物理学

Academic Significance and Societal Importance of the Research Achievements

高い時間分解能におけるイオン輸送計測から、イオン輸送の詳細な機構が明らかになった。また、合計9種類のイオンポンプロドプシンによるイオン輸送を初めて体系的に同条件で計測することで、イオン輸送に対する細胞環境の効果を検証し、ポンプ間での特性の違いを見出すことに成功した。これらの知見は光遺伝学等における光受容体を利用した生命の光操作技術や医療応用を技術応用への基盤となると期待される。