量子力学/分子力学計算反応ネットワークは,シトクロームP450カムとその変異体T252Aが酸化経路をどのように選択するかを明らかにしています
Binju Wang1, Chunsen Li2,3, Kshatresh Dutta Dubey1
1†Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
Journal of the American Chemical Society
|May 27, 2015
まとめ
量子力学/分子力学的計算により,P450酵素における新しい触媒経路が明らかになり",第2酸化物質"は排除され,T252A変異体による基板特異性エポキシデーションが説明される.
科学分野:
- 生物化学と酵素学
- コンピューティング・ケミストリー
- 構造生物学 構造生物学とは
背景:
- サイトクロームP450酵素は,重要な酸化反応を触媒化する.
- P450触媒のメカニズム,特に化合物I (Cpd I) の役割は広範に研究されています.
- P450camの変異 (Threonine-252-to-Alanine,T252A) は,陽子シャトルの役割を理解するために調査されました.
研究 の 目的:
- P450酵素における"第2酸化物質"という長年の疑問を調査する.
- P450cam T252A変異体の触媒メカニズムを解明する.
- T252A変異体による5メチレニルカンフォールのエポキシド化に起因する経路を特定する.
主な方法:
- 量子力学/分子力学 (QM/MM) の計算を用いた.
- 酸化候補物質:Cpd I,鉄酸化水素酸化物,および鉄酸化水素過酸化物 (Fe ((III) ((O2H2)) を調査することによって,反応性ネットワークが生成されました.
- 中間安定剤における基質とタンパク質の相互作用の役割を分析した.
主要な成果:
- Fe (III) (O2H2) の中間物質によって開始される"第2結合経路"が特定されました.
- この経路は,O-O同解とH抽象化を含み,Cpd I形成につながります.
- サブストラット (5-メチレニルカンフォール) とタンパク質の相互作用は,Fe ((III) ((O2H2) の持続性と反応性を決定し,エポキシデーションに影響を与え,カンフォールの酸化を防ぐ.
結論:
- この研究は"第2の酸化物質"を排除し,P450cam.cam.における追加の結合経路を特定した.
- T252A変異は,Fe (III) (O2H2) を含む新しい経路を基板エポキシデーションに可能にします.
- 結果は,シトクロームP450カムの修正された触媒サイクルにつながり,基質-タンパク質の相互作用を強調しました.
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