酸素同位体効果の計算によって分析されたアルカリ性ファスファタゼにおける基質と移行状態の結合
1Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin , Madison, Wisconsin 53706, United States.
Journal of the American Chemical Society
|August 20, 2016
まとめ
アルカリリン・フォスファターゼ (AP) は,過渡状態を安定させ,触媒効率を高めるために,事前に組織された活性部位を使用します. この研究は,基質変形と結合同位体の効果がAPの触媒力にどのように貢献するか示しています.
科学分野:
- 生物化学
- コンピュータ化学
- 酵素学
背景:
- 酵素は重要な生物学的触媒で 医療や産業に大きな可能性を秘めています
- アルカリリンフォスファターゼ (AP) は,触媒メカニズムを詳細に調査する高度に効率的な酵素です.
研究 の 目的:
- 計算方法を用いてアルカリリンファスファターゼ (AP) の触媒メカニズムを解明する.
- APの触媒能力に対する様々な同位体効果の貢献を調査する.
- AP反応における移行状態 (TS) と基質結合の理解を精進する.
主な方法:
- 量子力学の計算
- ハイブリッド量子力学/分子力学 (QM/MM) シミュレーション
- 様々なリン酸エステル基板の均衡同位体効果 (EIEs),結合同位体効果 (BIEs) および運動同位体効果 (KIEs) のモデリング.
主要な成果:
- 計算された同位体効果は実験データとよく一致する.
- 提案された移行状態 (TS) モデルは,以前の解釈とは異なる.
- 同位体の結合への影響は,V/Kで測定されたKIEを著しく影響する.
- 基底状態 (GS) の基底変形とTSのような形状の優先結合が観察されました.
結論:
- この研究は,AP触媒における測定された同位体効果の精密な解釈を提供します.
- 基質変形と酵素前組織化を伴う新しいメカニズムが提案されています.
- この発見は,酵素触媒における結合同位体効果と活性部位の前組織化の重要性を強調し,従来型の誘導適合モデルに異議を唱える.
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