肝臓アルコールの脱水酸化酵素におけるヒドリド転送:量子力学,運動同位体効果,酵素運動の役割
S R Billeter1, S P Webb, P K Agarwal
1Department of Chemistry, 152 Davey Laboratory, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Journal of the American Chemical Society
|November 8, 2001
まとめ
肝アルコール脱水素酶 (LADH) 量子ダイナミクスは,水素トンネリングが鍵であることを明らかにします. 酵素の動きは,VAL-203の相互作用と同様に,反応速度と酵素活性に大きな影響を与えます.
科学分野:
- バイオケミストリー バイオケミストリー
- 化学物理 化学物理
- コンピューティング・ケミストリー
背景:
- 肝臓アルコール脱水素酵素 (LADH) は,水素移転反応に不可欠です.
- 酵素触媒における量子効果を理解することは,反応機構の説明に不可欠です.
研究 の 目的:
- LADHによって触媒化された水素移転の量子ダイナミクスを調査する.
- 酵素活性における核および電子量子効果の役割を明らかにする.
- 酵素運動と触媒効率を相関させるため.
主な方法:
- 溶解酵素全体のリアルタイムダイナミックシミュレーション.
- 電子量子効果のための経験的なバレンスの結合の可能性.
- 核量子効果のための混合量子/古典分子ダイナミクス (MD).
- 量子トランジション (MDQT) によるリアルタイム分子ダイナミクス. 表面をジャンプする軌道.
主要な成果:
- 計算されたデウテリウムとトリチウムの運動同位体効果は,実験データと一致しています.
- 提供者-受容者軸に沿って水素トンネルの証拠が見つかりました.
- ユニットに近い伝送係数は,最小のバリア再交差を示します.
- ドナーと受容体の距離,VAL-203の相互作用を含む酵素の動きは,活性化自由エネルギーバリアに大きな影響を及ぼします.
結論:
- 量子効果,特に水素トンネリングは,LADH触媒の根本的な役割を果たしています.
- 酵素の動き,特にVAL-203がTHR-178と共酵素との相互作用により,自由エネルギーバリアと酵素の活性が調節されます.
- 酵素活性に対するVAL-203変異の効果は,主に不均衡の動態ではなく,変化した均衡の自由エネルギーによるものです.
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