Structural dynamics of K+ channel imaged by high-speed atomic force microscopy

2021 Fiscal Year Final Research Report

• Project/Area Number: 17H05058
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: General physiology
• Research Institution: Kanazawa University
• Principal Investigator: Sumino Ayumi 金沢大学, ナノ生命科学研究所, 助教 (80717140)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: イオンチャネル / 高速原子間力顕微鏡

Outline of Final Research Achievements

The plan was to develop a simultaneous tip-scanning high-speed AFM and electrophysiology measurement system to observe the nanostructure and function of channels, but the fabricated tip-scanning high-speed AFM did not work stably. Therefore, we changed our plan and replaced the tip-scanning high-speed AFM with a sample-scanning high-speed AFM with stable operation. When the voltage-gated Na+ channels in lipid membranes were measured with the sample-scanning high-speed AFM, a pore domain (PD) structure was observed, in which four particles were assembled in a square shape. Surrounding them are smaller particles closely packed, which are considered to be voltage sensor domains (VSDs). In mutants with altered voltage dependence, VSD-like particles dissociate from the PD, revealing an association and dissociation of intramolecular motifs related to voltage dependence.

Free Research Field

生物物理学

Academic Significance and Societal Importance of the Research Achievements

電位依存性チャネルは生理機能の維持に欠かせない重要な分子群であるが、その電位依存的な開閉の際の構造変化は不明点が多い。本研究は脂質膜中における電位センサードメインとポアドメインの位置関係を一分子レベルで直接観察した初の結果であり、電位依存的開閉機構の完全解明に向けて重要な知見となった。