モリブデンコファクターの酸化形態に対するピランサイクリングとプテリン構成の影響
Douglas R Gisewhite1, Jing Yang2, Benjamin R Williams1
1Department of Chemistry , Bryn Mawr College , Bryn Mawr , Pennsylvania 19010 , United States.
Journal of the American Chemical Society
|September 12, 2018
まとめ
モリブドプテリン (MPT) リガンドのピラン環閉塞はモリブデン中心を電子的に結合し,酵素活性を調節する. この分子スイッチメカニズムは,ピラノプテリンモリブデン酵素の酸化還元特性を調整する.
科学分野:
- バイオ有機化学
- 酵素メカニズム
- 有機金属化学
背景:
- 単核モリブデンとボルンガムの酵素は,モリブドプテリン (MPT) リガンドを使用する.
- MPTには,ピラノプトリンのグループに結合した金属結合ディチオレンケラートが含まれています.
- MPTのピラン循環/分裂は,金属中心の反応性を調節すると仮定されている.
研究 の 目的:
- MPTのピランサイクライゼーションがディチオレンとプテリンの電子通信を調節する方法を調査する.
- ピランサイクリングがモリブデン触媒部位の電子環境をどのように変化させるかを決定する.
- 詳細な研究のためにMo-MPTコファクターの小分子モデルを設計する.
主な方法:
- サイクルボルトメトリ
- 振動光譜 (FT-IRとラマン)
- 電子吸収光学
- X線吸収スペクトル
主要な成果:
- ピランリングの閉塞は,MoOの伸縮周波数とMoV/IVの減少ポテンシャルに明確な変化をもたらします.
- ディヒドロピラノプテリンのリガンドは,コプラナー形状を通してモ-ディチオリン群に電子的に結合する.
- 強いディチオレン → プテリンの電荷移転は,結合システムのスペクトル学的な特徴である.
- ピランブリッジの欠如は,プテリンの回転につながり,システムを切り離します.
結論:
- ピランサイクライゼーションは,Mo-MPTモデルのプテリンとディチオレンユニットを電子的に結合する.
- この結合により,電子欠乏のプテリンは,モリブデン環境を調節することができます.
- MPTピランサイクライゼーション/シシションは分子スイッチとして作用し,ピラノプテリンモリブデン酵素の酸化還元特性を調節する.
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