ニトロゲーゼFeタンパク質からMoFeタンパク質への電子移転の適合ゲート
Karamatullah Danyal1, Diana Mayweather, Dennis R Dean
1Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, USA.
Journal of the American Chemical Society
|May 1, 2010
まとめ
窒素酵素Feタンパク質の電子移転は,粘度ではなく,形状の変化によってゲートされます. オスモス圧は,このゲートメカニズムを明らかにし,その過程で水分子が重要な役割を果たします.
科学分野:
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
- バイオエネルギー学 バイオエネルギー学
背景:
- 窒素酵素 Fe タンパク質 ([4Fe-4S]クラスター) は MoFe タンパク質に電子を転送する.
- 電子移転 (ET) はATPの水解と結びついています.
- 窒素酶複合体の形状の変化は,ETの"ゲート"を示唆しています.
研究 の 目的:
- 窒素酶における電子移転の"ゲーティング仮説"を調査するために.
- 複合体内電子伝送における構成変化の役割を理解する.
- 電子移転とATP水解の関係を解明する.
主な方法:
- Fe ((赤) タンパク質のMoFeタンパク質による複合内酸化を研究した.
- 形状制御を調査するために様々な溶液を使用した.
- 測定されたオスモティック圧力と粘度効果.
- 評価された溶媒の運動同位体効果.
主要な成果:
- 電子伝送ゲーティングは,オスモス圧力の変化への反応によって確認されています.
- この反応には少なくとも80個の水分子が関与しています.
- 粘度の変化は電子伝送率に影響を与えなかった.
- 溶媒の運動同位体効果の欠如は,ATPの水解がETの速度を制限しないことを示唆しています.
結論:
- オスモス圧力と水の相互作用によって調節される形状の変化,窒素酶におけるゲート電子移転.
- 電子の移転はATPの水解とPiの放出に先行し,これらの出来事を分離する.
- ATPの水解結合と電子移転のメカニズムは依然として複雑である.
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