[FeFe]ヒドロゲネーゼは,COブリッジ付き中間物質のみで動作する,というスペクトロスクープと計算による証拠
James A Birrell1, Vladimir Pelmenschikov2, Nakul Mishra3
1Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany.
Journal of the American Chemical Society
|December 11, 2019
まとめ
[FeFe]ヒドロゲネーゼは,主要中間状態でブリッジングヒドリドではなく,ブリッジングカルボニル (CO) を利用する. この発見は,これらの高度に活性な水素変換酵素のメカニズムを明らかにします.
科学分野:
- 生物化学
- 酵素学
- バイオ有機化学
背景:
- [FeFe]ヒドロゲナーゼは水素 (H2) の変換に不可欠な酵素である.
- 正確な触媒機構,特に還元された中間物質 (HredH+とHsredH+) の同一性は議論されている.
- 既存のモデルは,これらの状態で半ブリッジ化COまたはブリッジ化水素を提案しています.
研究 の 目的:
- [FeFe]ヒドロゲネーゼ中間体の構造とメカニズムの詳細を解明する.
- HredH+ と HsredH+ の状態におけるブリッジングCO とブリッジング水素の存在に関する論争を解決する.
- これらの中間物質の触媒能力の実験的証拠を提供すること.
主な方法:
- 低温赤外線 (IR) スペクトロスコーピー
- 核共振振動スペクトロスコーピー (NRVS)
- 密度関数理論 (DFT) の計算
主要な成果:
- HsredH+ と HredH+ の状態でブリッジングカルボニル (CO) の保持を実験的に確認した.
- 両方の中間状態でブリッジング水素の証拠は見つかりませんでした.
- この発見は,これらの状態が統合され,活性である触媒サイクルモデルを支持する.
結論:
- 橋渡しCOは橋渡しヒドリドではなく,主要な[FeFe]ヒドロゲネーゼ中間体に存在します.
- 亜群の間の陽子結合電子の移転は,酵素の効率と可逆性にとって不可欠である.
- この研究は,高度に活性なH2変換酵素のメカニズムを明らかにします.
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