[FeFe]-ヒドロゲネーゼHクラスタの組成は,HydAの構造 ((DeltaEFG) で段階的に明らかになりました
David W Mulder1, Eric S Boyd, Ranjana Sarma
1Astrobiology Biogeocatalysis Research Center, Montana State University, Bozeman, Montana 59717, USA.
Nature
|April 27, 2010
まとめ
この研究は,[FeFe]-ヒドロゲナース (HydA) 酵素が活性部位を組み立てる方法を明らかにしています. [4Fe-4S]クラスターが最初に挿入され,2Feサブクラスターが特殊な熟成機械を介してそれに続くことが示されています.
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
- 酵素学 酵素学とは
背景:
- Fe-Sクラスターを備えた複雑な酵素は,炭素固定や水素代謝などのプロセスに不可欠です.
- 水素代謝には[NiFe]-,[FeFe]-,[Fe]-ヒドロゲネーゼが含まれている.
- [FeFe]-水素酶活性部位 (H-クラスター) には [4Fe-4S] と 2Feサブクラスターがあり,後者の合成および挿入機構は不明である.
研究 の 目的:
- [FeFe]-ヒドロゲネーゼにおけるHクラスター組成のメカニズムを解明する.
- Hクラスタのコンポーネントの段階的な合成と挿入のための構造的基礎を決定する.
主な方法:
- HydA ((DeltaEFG) のX線結晶学 (H群の生物合成遺伝子が欠けている).
- HydAの進化に関する系統遺伝分析.
主要な成果:
- HydA ((DeltaEFG) の構造は, [4Fe-4S] クラスタと2Feサブクラスタのための開いたポケットを明らかにしました.
- 証拠は,段階的なHクラスター組成を示唆しています: [4Fe-4S]を宿主機械で挿入し,2Feサブクラスターの合成とHydE,HydF,HydGの挿入が続きます.
- 2Feサブクラスタの挿入は,一時的なカチオンのチャネル経由で起こる可能性があります.
結論:
- [FeFe]-ヒドロゲネーゼHクラスタの組み立ては,段階的なプロセスです.
- HydAは,2Feサブクラスターを欠いたNar1型の祖先から進化した可能性があり,その後エウカリオットで獲得された.
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