窒素酵素フェモコファクターの中間原子:ENDORとESEEMは,それが窒素ではないことを証明しています
Tran-Chin Yang1, Nathan K Maeser, Mikhail Laryukhin
1Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
Journal of the American Chemical Society
|September 15, 2005
まとめ
窒素酵素 MoFe タンパク質は
科学分野:
- バイオケミストリー バイオケミストリー
- バイオ・オーガニック化学 バイオ・オーガニック化学
- 構造生物学 構造生物学とは
背景:
- 窒素酵素複合体は,生物学的窒素固定に不可欠です.
- MoFeタンパク質の活性部位には,複合体 [MoFe7S9:ホモサイトレート] FeMo-コファクターが含まれています.
- 以前のX線結晶学では,FeMo共因子内の未確認の原子 (X) が示唆されていた.
研究 の 目的:
- FeMo共因子内の未確認の原子 (X) が窒素であるかどうかを判断する.
- 窒素酵素MoFeタンパク質の活性部位の組成を調べるために.
主な方法:
- X線結晶学は,X原子の電子密度を特定するために使用されました.
- Q帯電子核二重共振 (ENDOR) と電子スピンエコーエンベロープ調節 (ESEEM) のスペクトロスコピが使用されました.
- MoFeタンパク質と14Nまたは15Nイソトープで育ったNMF抽出FeMo共因子からのスペクトル信号の比較.
主要な成果:
- 単一のN,O,またはC原子と一致する電子密度が観察されました.
- 窒素 (14Nまたは15N) に起因するスペクトル信号は,タンパク質と限定的に関連していました.
- これらの窒素特異信号は,FeMoコファクターの抽出時に失われました.
結論:
- FeMo共因子内の未確認の原子Xは窒素ではない.
- 放射光学で検出された窒素原子は,FeMo-コファクターそのものではなく,タンパク質成分にあります.
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