タイロシンからプロトン結合電子の移転:分子内プロトン移転距離に強い速度の依存性がある

Ming-Tian Zhang¹, Tania Irebo, Olof Johansson

¹Department of Photochemistry and Molecular Science, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden.

Journal of the American Chemical Society

|August 5, 2011

まとめ

この研究は,バイオミメティック複合体における陽子結合電子伝送 (PCET) が,陽子伝送距離に依存していることを示しています. より短い距離は,分子内PCET反応の速度と運動同位体効果を高めます.

科学分野:

バイオミメティック化学
フォトケミストリーフォトケミストリー
物理化学物理化学とは

背景:

陽子結合電子移転 (PCET) は,生物系において極めて重要です.
PCETメカニズムを理解するには,モデルシステムを研究する必要があります.
結合的に結合されたRu (II) (bpy) (iii) -チロシン複合体は,効果的なバイオミメティックモデルとして機能する.

研究の目的:

陽子伝達距離が分子内PCET率に及ぼす影響を調査する.
PCET運動のドナーと受容体の分離による依存を実験的に検証する.
PCETの促進における内部基地の役割を探求する.

主な方法:

内部塩基を持つバイオミメティックRu(II) ((bpy) ((3) -チロシン複合体の合成.
レーザーフラッシュ/クエンチ実験を用いた光酸化により,Ru (III) 種を生成する.
速度定数と運動同位体効果を決定するための運動分析.

主要な成果:

光酸化により,チロシンからの遠距離電子の移転が始まり,内部ベースへの陽子の移転が加わります.
分子内PCETの速度常数と運動同位体効果は,陽子の移動距離に強く依存していた.
実験データにより,ドナーと受容体の距離とPCETの効率の相関が確認されました.

結論:

この研究は,分子内PCETの距離依存性に関する実験的証拠を提供します.
バイオミメティックモデルは,複雑な生物学的電子転送プロセスを効果的に真似します.
陽子ドナー-受容体の距離を正確に制御することは,PCETの反応性を調節する鍵です.

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