B12依存メチルマロニル-CoAミュータゼにおける根幹生成のメカニズムに関する計算による洞察
Renata A Kwiecien1, Ilja V Khavrutskii, Djamaladdin G Musaev
1Institute of Applied Radiation Chemistry, Technical University of Lodz, Poland.
Journal of the American Chemical Society
|January 26, 2006
まとめ
メチルマロニル-CoAミュータゼは,コバルト-炭素結合の割れ前に構成の変化を含む段階的なメカニズムを使用します. ラジカル形成に不可欠なこのプロセスは,重要なエネルギーと構造の詳細を明らかにするために計算モデル化されています.
科学分野:
- バイオケミストリー バイオケミストリー
- コンピューティング・ケミストリー
- 酵素学 酵素学とは
背景:
- メチルマロニル-CoAミュータゼ (MMCM) は,メチルマロニル-CoAのイソメリ化に不可欠なB12依存酵素である.
- 5'-デオキシアデノシルコバラミン (AdoCbl) コファクターにおけるコバルト-炭素結合の裂解のメカニズムを理解することは,MMCMの機能にとって極めて重要です.
研究 の 目的:
- 計算的方法を用いてMMCMによって触媒化された同解性Co-C5'結合解離の詳細なメカニズムを解明する.
- 反応中のAdoCblコファクターにおける構造変化の役割を調査する.
主な方法:
- ONIOM (Our Own is from the Netherlands, Ours is from the Netherlands) の量子力学による計算が採用されました.
- Co-C5'結合割れのための移行状態構造と反応エネルギーが決定されました.
主要な成果:
- Co-C5'結合割れは,5'-デオキシアデノシン部分の構造変化によって開始される段階的なプロセスです.
- 移行状態は,著しい延伸 (約. Co-C5'ボンドの0.5 Å) であった.
- 全体的な活性化バリアは約10 kcal/molで,基質産物は初期複合体よりも少し安定性が低い.
結論:
- 形状的再配置がホモリシスに先行し,急性生成を容易にする.
- 計算されたエネルギーと構造の変化は,MMCM触媒の詳細なメカニズム的な理解を提供します.
- 5'-デオキシアデノシルラジカルの位置は,メチルマロニル-CoAからの水素原子の移転に最適化されています.
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