Methanocaldococcus infernusの窒素化コファクターマチューラーゼNifBに存在する3つの鉄硫黄群の電子パラマグネティック共振特性
Jarett Wilcoxen1, Simon Arragain2, Alessandro A Scandurra2
1Department of Chemistry, University of California , Davis, California 95616, United States.
Journal of the American Chemical Society
|June 9, 2016
まとめ
この研究では,Methanocaldococcus infernusのNifB酵素は,ラジカルS-アデノシルメチオニン (SAM) 酵素であることを示しています. 窒素酶機能に不可欠な鉄モリブデンコファクター (FeMo-co) の成熟に重要な役割を果たします.
科学分野:
- 生物化学
- 酵素学
- 微生物学
背景:
- 窒素酵素は生物学的窒素固定に不可欠である.
- 鉄モリブデン共因子 (FeMo-co) は窒素酵素活性に不可欠である.
- NifBはFeMo- coの生物合成経路における重要な酵素である.
研究 の 目的:
- メタノゲンであるメタノカルドコックス・インフェルナスの NifB のメカニズムを調査する.
- NifB共因子 (NifB-co) の形成におけるNifBの役割について説明する.
- NifBにおける補助 [Fe-S]クラスタの機能を明らかにする.
主な方法:
- 電子パラマグネティック共振 (EPR) スペクトロスコーピー
- 酵素活性を評価する生化学的測定法
- ラジカルSAM酵素機構の特徴
主要な成果:
- M. infernusのNifBは,ラジカルS-アデノシルメチオニン (SAM) 酵素として機能する.
- NifBはSAMを還元的に割って5'-デオキシアデノシン基を形成する.
- SAM結合および補助クラスターを含む3つの [4Fe-4S]クラスターが特徴付けられました.
- 補助クラスターへの窒素調整は,NifB-coの形成と解離に役割を果たすことを示唆している.
結論:
- M. infernusからのNifBはFeMo-co成熟に適しています.
- 特定された補助クラスターは,NifB-co形成のための基板である可能性が高い.
- NifBのメカニズムを理解することで,窒素酵素生物合成の洞察が得られます.
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