核電二重共鳴スペクトロスコピーは,二核ヒドロラーゼによる触媒に含まれるヒドロキソブリッジ核フィルの証拠を示しています

Stoyan K Smoukov¹, Luca Quaroni, Xuedong Wang

¹Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.

Journal of the American Chemical Society

|March 14, 2002

まとめ

この研究では電子核二重共振 (ENDOR) 光譜を用いて,紫酸リン酸ファスファタゼを調査した. 発見は,端末ではなく,ブリッジングヒドロキシドが,子宮内フェリン触媒の鍵であることを明らかにします.

科学分野:

バイオケミストリーバイオケミストリー
生物物理化学生物物理化学
酵素学酵素学とは

背景:

紫酸リン酸塩酵素 (PAP) は,リン酸代謝に関与する重要な酵素である.
活性部位の溶媒の調整を理解することは,PAPの触媒メカニズムを解明するために不可欠です.
以前の結晶構造には,活性酵素内の溶媒リガンドの直接的な証拠がない.

研究の目的:

溶媒分子を,ウテロフェリン (Uf) の活性二金属中心に調整して識別する.
Ufの触媒機構における溶媒由来リガンドの役割を調査する.
Ufおよびその複合体の溶媒分子とMoO(4),AsO(4),PO(4) との調整を決定する.

主な方法:

(2) H Q帯 (35 GHz) パルス式電子核二重共振 (ENDOR) スペクトロスコーピーを利用しました.
子宮内フェリンの二金属中心の活性混合バレンスの (Fe(3+) Fe(2+)) 形態を分析した.
試験されたUfは,その本来の状態と,リン酸塩,アルセネート,およびモリブド酸塩アニオンとの複合体である.

主要な成果:

ブリッジングヒドロキシードとターミナル水/ヒドロキシードをFe ((2+) に結合して,UFの二核中心で特定した.
Fe3+) センターに結合した終端水/水酸化物は見つかりませんでした.
アニオン結合時にターミナル水の損失が観察され,ブリッジング水酸化物は残った.

結論:

この結果は,終端のFe3+結合核フィルを含む水解機構を排除している.
この発見は,橋渡しヒドロキシドが核愛者として作用する触媒メカニズムを支持する.
この研究は,PAP触媒における溶媒由来リガンドの役割に関する直接的なスペクトロスコピ的証拠を提供します.

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