静止状態の構造と電圧ゲートされたナトリウムチャネルのゲートメカニズム
Goragot Wisedchaisri1, Lige Tonggu2, Eedann McCord1
1Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
Cell
|July 30, 2019
まとめ
研究者は,電圧ゲートされたナトリウム (NaV) チャンネルの静止状態構造を解明し,S4セグメントの動きがチャネルゲートを制御する方法を明らかにした. これは,電圧センサーとアクティベーションゲート閉鎖のための完全なメカニズムを提供します.
科学分野:
- バイオ物理学
- 構造生物学
- 分子神経科学
背景:
- ボルテージゲートナトリウム (NaV) チャンネルは,興奮性細胞の電気信号伝達に不可欠である.
- 静止状態の構造を理解することは,電圧依存のゲートメカニズムを明らかにする鍵です.
- NaVチャネルの静止状態に関する以前の構造データは限られている.
研究 の 目的:
- 祖先の細菌のナトリウムチャネル (NaVAb) の静止状態の冷凍-EM構造を決定する.
- NaVチャネルにおける電圧依存ゲーティングの完全なメカニズムを解明する.
- 高解像度構造の洞察を電圧センサーとアクティベーションゲート機能に提供します.
主な方法:
- 静止状態を安定させるため,電圧シフト変異とNaVAbの二硫化クロスリンクを設計した.
- 高解像度構造データを得るために,冷凍電子顕微鏡 (cryo-EM) を利用した.
- 詳細なゲートメカニズムを提案するために構造的特徴を分析しました.
主要な成果:
- 静止状態のNaVAbの冷凍-EM構造を決定した.
- S4セグメントが細胞内に位置し,ゲーティング電荷が膜外電場を通過する.
- S4とS5のリンクを繋ぐ"肘"を形成し,S6の活性化ゲートを緊縮し,孔が開くのを防ぐ.
結論:
- 構造は古典的な
- スライディングヘリックス
- ボルテージセンサーのモデル
- 電圧センサーの動き,毛穴の開き,アクティベーションゲートの閉塞を含む完全なゲートメカニズムが提案されています.
- 高解像度構造は,NaVチャネルゲートダイナミクスに関する前例のない詳細を提供します.
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