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合成ヘムとヘム・銅複合体のシステムにおける一酸化炭素と一酸化窒素のリガンドダイナミクス
Heather R Lucas1, Gerald J Meyer, Kenneth D Karlin
1Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
Journal of the American Chemical Society
|September 10, 2009
まとめ
研究者らは,鉄と銅の間の分子間一酸化窒素 (NO) と一酸化炭素 (CO) の前例のない移転を達成しました. この研究は,異なる結合親和性と転送率を明らかにし,ヘム-銅酵素機構の洞察を提供している.
科学分野:
- バイオ・オーガニック化学 バイオ・オーガニック化学
- フォトケミストリー フォトケミストリー
- 酵素メカニズムの仕組み
背景:
- 窒素一酸化物 (NO) と一酸化炭素 (CO) は,生物系における重要なシグナル伝達分子および結合体である.
- ヘム・コッパータンパク質は,細胞呼吸とシグナル伝達経路において重要な役割を果たします.
- リンガンド転送機構を理解することは,酵素の機能を明らかにする鍵です.
研究 の 目的:
- 鉄と銅の中心間のNOとCOの分子間移転を調査する.
- これらのリガンド転送プロセスの運動学と熱力学を特徴づけるために.
- サイトクロームc酸化酵素などのヘム-銅酵素機能への影響を調査する.
主な方法:
- トランジエント吸収レーザーフラッシュ光分解は,リガンド移転を研究するために使用されました.
- 6座標の鉄性ヘム複合体と銅 ((I)) 複合体を構成するモデルシステムが合成されました.
- 銅の異なるリガンド協調環境 (((I) が結合偏好を調査するために使用されました.
主要な成果:
- 鉄と銅の間の反転可能な分子間NOとCOの移転の最初の観察を実証しました.
- 銅 (I) は,COと比較してNOに対するより低い親和性を示すことが判定された.
- COと比較してNOの結合率がヘム中心に高くなることが観察されました.
結論:
- この研究は,金属タンパク質間のNOとCOの転送のための新しいメカニズムを確立しています.
- 発見は,異なるリガンドの親和性および移転速度が生物学的機能にとって重要であることを示唆しています.
- 観察されたヘム-NO結合運動は,シトクロームc酸化酵素のメカニズムと一致しています.
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