Single molecule measurement of ligand bindings to the acetylcholine receptor channel

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K06157
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 43040:Biophysics-related
• Research Institution: Okayama University
• Principal Investigator: Ide Toru 岡山大学, ヘルスシステム統合科学学域, 教授 (60231148)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: イオンチャネル / １分子計測 / 単一チャネル電流計測 / １分子イメージング

Outline of Final Research Achievements

Single molecule imaging system utilizing the local surface plasmon at the tip of a sharp gold electrode was developed. The electrode was fabricated by electro-chemical etching the tip of a thin gold wire. An automatic etching system was developed to increase fabrication efficiency. Fluorescence observation was performed using fluorescent dyes with low quantum yields, and single molecules of fluorescent dyes were observed.
The electrode surface was modified to be hydrophilic, and an artificial lipid bilayer membrane was successfully formed on the electrode surface. Using this artificial membrane, single channel current analysis of channel proteins, channel-forming peptides, and pore-forming toxins was successfully performed.
The above artificial membrane method has succeeded in significantly improving the efficiency of channel current measurement compared to conventional methods, and has also enabled automated measurement using a robot.

Free Research Field

生物物理学

Academic Significance and Societal Importance of the Research Achievements

チャネル蛋白は機能の1分子解析（単一チャネル電流解析）が最も進んだ蛋白である。各々のチャネルに対して、詳細な状態遷移モデルが提案されており、本研究の成果はモデルの直接検証手段を与える。また、チャネルは１分子のリガンド結合と機能の相関を高時間分解で観測できる蛋白であり、計測によって得られた知見を蛋白一般の分子機構の理解に拡げることも可能となる。また、チャネル蛋白は膜のイオンの透過性を制御することよって、多岐に渡る生命活動おいて重要な役割を果たしている。チャネル蛋白一般の活性化分子機構を詳細に知ることは、科学的な興味に止まらず、医療、創薬などの分野においても重要である。