マルチドラッグABCトランスポーターBmrAにおける非対称なATP水解を固体NMRで検出
Denis Lacabanne1, Thomas Wiegand1, Margot Di Cesare2
1Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland.
Journal of the American Chemical Society
|July 1, 2022
まとめ
この研究は,ABCトランスポーターでATPの水解がどのように起こるかを明らかにしています. 固体 NMR を用いて 研究者たちは ATP 結合部位が水解の間に対称性を失い その過程の後には 回復することを発見しました
科学分野:
- 生物化学
- 構造生物学
- 分子生物物理学
背景:
- ATP結合カセット (ABC) トランスポーターによるATP水解のメカニズムは,それらの機能に不可欠ですが,まだ完全に理解されていません.
- ABCトランスポーターは,多剤耐性を含む細胞プロセスにおいて重要な役割を果たします.
研究 の 目的:
- マルチドラッグ ABC トランスポーター BmrA の触媒サイクル中の構造変化と動態を解明する.
- 先進的なNMR技術を用いてBmrAの核酸結合状態 (プレヒドロリチス,トランジション,ポストヒドロリチス) を調査する.
主な方法:
- 固体NMRスペクトロスコーピーを利用して,コンフォメーションダイナミクスを探査した.
- 特定の触媒状態を捕まえるために,部位指向型変異 (E504A変異体) とATP類似体を使用した.
- 分析されたC NMRスペクトルとP-P2D相関スペクトルは,核酸結合部位の対称性とダイナミクスを評価した.
主要な成果:
- P NMRは,前水解状態の両方の部位に強いATP結合を示した.
- 移行状態では,BmrAのダイマー対称性が破られ,あるサイトはADP:Mg2+:vanadateと緊密に結合し,他のサイトは開いた.
- 水解後状態では,両方の部位にADP結合が弱く,対称性が回復した.
結論:
- この研究は,ATPの水解中にBmrAの核酸結合部位の対称性の喪失と,その後の回復を示しています.
- これらの発見は,分子レベルでABCトランスポーターの触媒機構に関する重要な洞察を提供します.
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