ニトロゲンアースのFeMo-co活性部位の水素化学
1School of Chemistry, University of New South Wales, Sydney 2052, Australia.
Journal of the American Chemical Society
|August 4, 2005
まとめ
窒素酵素酵素は,鉄モリブデン共因子 (FeMo-co) のS3B部位に水素が入る新しいメカニズムによるN(2) 水素化を触媒化する. この研究は,FeMo-co内の新しい水素化学と調整原理を詳細に説明し,基板水素化を説明します.
科学分野:
- バイオケミストリーとバイオ有機化学
- 酵素のメカニズムは
- 窒素酵素酵素の触媒である.
背景:
- 鉄-モリブデン共同因子 (FeMo-co) での窒素酶触媒によるN(2) 水素化の正確な化学的メカニズムは未だに曖昧である.
- 水素 (H ((2)),基板,およびCOのような阻害剤の役割を理解することは,触媒経路の解明に極めて重要です.
- FeMo-co上の水素原子とH(2) の蓄積と協調は,窒素酶機構にとって根本的なものです.
研究 の 目的:
- FeMo-co活性部位内の初期水素 (H) 入口点と,その後の調整化学を解明する.
- FeMo-co領域におけるHとH (2) の協調のための多様な可能性を特徴づける.
- HD反応を含む,H(2) 生成,移動,および基板水素化の詳細なメカニズムを提案する.
主な方法:
- FeMo-coおよび関連するアミノ酸残基の包括的な化学モデルで検証された密度関数計算を使用しました.
- FeMo-co活性部位で,H原子とH2の80以上の異なる協調の可能性を特徴付けました.
- H原子とH(2) の動き,生成,結合,解離のための反応プロファイルを計算した.
主要な成果:
- FeMo-co.のS3B原子で終結する水連鎖を介して新しいHエントリーメカニズムを提案しました.
- 八面体 Fe ((S) ((3) ((H)) ((2)) ((2))) を含む,前例のない調整構造を特定しました.
- FeMo-co水素化学の確立された一般原則:S結合Hのステレオ化学的移動性,微分化Fe調整部位,および協調性アロステリー.
結論:
- S3Bは,提案されたH ((+) シャトルメカニズムで,主要なH入口部位として特定されています.
- この研究は,FeMo-co.におけるMoの存在と末端の微分化のメカニズム的根拠を提供します.
- 最近の実験捕獲データと一致する,水素化された中間物質のための合意モデルが提案されています.
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