非慣例の S-アデノシルメチオニン酵素によって形成される有機金属複合体
Min Dong1, Masaki Horitani2, Boris Dzikovski1
1Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States.
Journal of the American Chemical Society
|July 29, 2016
まとめ
Pyrococcus horikoshiiのDph2酵素は新しいアナログを割って 独特の有機金属複合体を明らかにします この発見は,S-アデノシルメチオニンの酵素機構と鉄-硫黄のクラスター反応性の理解を進める.
科学分野:
- 生物化学
- 酵素学
- 構造生物学
背景:
- Pyrococcus horikoshii Dph2 (PhDph2) は S-アデノシルメチオニン (SAM) 酵素である.
- ディフタミド生物合成の初期段階において重要な役割を果たします.
- PhDph2は,SAM分裂を触媒化し,3-アミノ-3-カルボキシプロピル (ACP) ラジカルを形成する.
研究 の 目的:
- PhDph2の反応メカニズムを調査する.
- SAMのアナログ割れで形成されたパラマグネティック種の性質を明らかにする.
- 酵素の [4Fe-4S] クラスタと反応産物の相互作用を理解する.
主な方法:
- 3カルボキシアリル基を持つ新しいSAM アナログ (SAMCA) の合成
- SAMCAをPHDph2によって酵素分解する.
- 同位体で標識されたSAMCAを用いた電子核二重共振 (ENDOR) 光譜法.
主要な成果:
- PhDph2はSAMCAを分裂させ,パラマグネティックな (S=1/2) 種を生成した.
- この種はα-スルフィニル-3-ブテノ酸と [4Fe-4S] クラスタの複合体として識別された.
- ENDORのデータは,アルケンと [4Fe-4S] クラスタのユニークな鉄の間のπ複合体を確認した.
結論:
- この研究は,アルケーンと有機金属複合体を形成する,SAMに関連する [4Fe-4S](+) クラスタの最初の例を示している.
- この発見は,PhDph2の触媒メカニズムに関する新しい洞察をもたらします.
- この結果は, SAM 酵素の根幹における [4Fe-4S] クラスタの既知の反応パターンを拡張している.
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