電圧感知領域の原子スケール運動は,スペクトル顕微鏡で測定されたカリウムチャネル内にある
A Cha1, G E Snyder, P R Selvin
1Department of Physiology, UCLA School of Medicine, Los Angeles, California 90095, USA.
Nature
|January 5, 2000
まとめ
研究者は,ランタナイドベースの共振エネルギー転送を使用して,電圧ゲートイオンチャネルにおける原子スケールの動きを測定しました. これらの発見は,カリウムチャネル電圧センサーが神経衝動を調節するために物理的に形状を変更する方法を明らかにします.
科学分野:
- バイオフィジックス 生物物理学
- 分子生物学は分子生物学である.
- 神経科学は神経科学である.
背景:
- ボルトゲートイオンチャネルは,神経衝動を調節する重要なトランスメブランタンパク質です.
- カリウムチャネルのS2およびS4セグメントは,電圧センサーとして作用しますが,それらの構成の変化は十分に理解されていません.
- これらのチャネルにおける電圧依存の距離変化の直接的な測定は欠けています.
研究 の 目的:
- シェイカーのカリウムチャネル内のサブユニット間の電圧依存の距離変化を測定する.
- チャネルの電圧センサーの構成変化の物理的性質を明らかにする.
- 電圧センシング中に物理的な動きと電気電荷の動きを結びつけるため.
主な方法:
- ランタニドベースの共振エネルギー転送 (LRET) を利用して,シェイカーのカリウムチャネルサブユニット上の特定の残留物間の距離を測定しました.
- コレレートされたLRET-derived距離測定と電圧センサ活動の電気生理学的記録.
主要な成果:
- 検出された電圧依存距離は,S4セグメントの近くで3.2 Åまで変化します.
- 測定された物理的運動と電圧センサーの電気的測定の間の直接的な相関が観察されました.
- 証拠によると,S4セグメントは回転と傾きを経験しますが,大きな膜経移転ではありません.
結論:
- 超膜タンパク質の原子スケールの動きを初めてin situで測定した.
- 物理的な形状の変化と電荷の移動の間の直接的なリンクを,電圧センサーで確立します.
- ボルテージゲートイオンチャネル機能のメカニズムに関する新しい洞察を提供します.
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