量子化学計算と組み合わせた高解像度ENDORスペクトロスコーピーは,ナイトロゲンゼ・ジャヌス中間物質E4の構造を明らかにします
Veronika Hoeke1, Laura Tociu2, David A Case3
1Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States.
Journal of the American Chemical Society
|July 17, 2019
まとめ
ジャヌス中間物質 (E4 ((4H)) は窒素酶の鍵である.
科学分野:
- 生化学と酵素学
- バイオ有機化学
- コンピュータ化学
背景:
- 窒素酵素は,N2からNH3への生物学的変換を触媒化する.
- E4{4H) 状態で
- ジャヌス
- このプロセスは極めて重要です.
- ENDORとDFTを用いた以前の研究では,FeMo-コファクター内のヒドリド結合構成の可能性が示唆されたが,最終的な構造解像度には欠けていた.
研究 の 目的:
- ナイトロゲンゼにおけるE4 ((4H) ジャヌス中間体のヒドリド結合構造を決定する.
- 触媒サイクルに関する以前の実験的および計算的モデルにおける曖昧さを解消する.
主な方法:
- 高解像度連続波 (CW) ストキャスティック1H-ENDOR実験で,改善された計測器具.
- Mims 2H ENDORと新しいパルス型ENDORプロトコル (PESTRE) で,超微細相互作用の兆候を決定する.
- 分析的点二極ハミルトニアンを使用した密度関数理論 (DFT) モデルと実験データを組み合わせる.
主要な成果:
- 実験データとDFTの計算は,E4 ((4H) ジャヌス中間物質の特定の最低エネルギー構造を特定するために収束した.
- 検証された構造は,FeMo-コファクター上の鉄イオンのペアを橋渡しする2つの並列のFe-H-Fe平面を特徴としています.
- これは,その後の反応ステップに不可欠な水素の位置づけの明確なイメージを提供します.
結論:
- E4 (((4H) ((a) 構造は,実験的に検証された最も低エネルギーのジャヌス中間物質を表しています.
- この正確な構造的決定は,窒素酵素によるN2減少のメカニズムを明らかにする.
- 統合された実験的および計算的アプローチは,酵素中間物質を研究するための堅固な方法を提供します.
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