Elucidation of the mechanism of the membrane potential-dependent structural change of the voltage-gated K+ channel

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K15033
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 43020:Structural biochemistry-related
• Research Institution: University of Tsukuba
• Principal Investigator: Harada Ayaka 筑波大学, 生存ダイナミクス研究センター, 助教 (00800476)
• Project Period (FY): 2021-04-01 – 2023-03-31
• Keywords: 電位依存性K+チャネル / 膜電位依存的構造変化 / SS-locking

Outline of Final Research Achievements

Voltage-gated K+ channels (Kv) open and close the pore domain (PD) gate through membrane potential-dependent structural changes of the voltage sensing domain (VSD). We introduced combinations of one Cys residue each into helices S1 and S4 of the VSD of KvAP and performed SS-locking analysis, which detects intramolecular disulfide (SS) bond formation by these two Cys residues when they are in close proximity. We assessed a total of 25 double-Cys mutants.
Because the residue pair interactions we obtained cannot all form if only a single protein conformation exists, our results indicate that multiple different conformations were stabilized by SS bond formation among the mutant proteins tested. We thus conclude that the structure of each mutant may reflect steps in the process of structural change between closed and open states of KvAP.

Free Research Field

構造生物学

Academic Significance and Societal Importance of the Research Achievements

KvAPは、真核生物由来Kvチャネルと類似した電気生理学的性質および立体構造を有することが明らかとなっているため、KvAPを用いてイオンチャネルに共通の機能構造を解明した上で、ヒトの痛覚や催不整脈性に関わるチャネルの機能・阻害機構を解明し、機能構造ごとにチャネル間を横断的に構造比較・特徴抽出することが可能となる。また、同じ機能構造・同じ部位に結合する阻害剤を同定できるため、これらのみで構造活性相関解析することにより、精度の高いファーマコフォアモデルを構築でき、各阻害機構を明らかにすることが出来る。