铁氧化在大肠杆菌铁氧化酶中心中的铁氧化,一个被设计为与H2快速反应但与O2缓慢反应的站点
Jacob Pullin1, Michael T Wilson1, Martin Clémancey2
1School of Life Sciences University of Essex Wivenhoe Park Colchester Essex CO4 3SQ UK.
概括
大肠杆菌菌 (EcBfr) 使用氧气 (O2) 氧化铁,形成过氧化 (H2O2). 这种H2O2然后迅速氧化更多的铁,表明EcBfrfr.
科学领域:
- 生物化学 生物化学
- 生物物理学的生物物理.
- 微生物学 微生物学
背景情况:
- 大肠杆菌菌 (EcBfr) 在铁的稳态中起作用.
- EcBfr 的铁氧化酶中心 (FC) 参与铁的氧化.
- 在 EcBfr FC 中,铁氧化成 O2 和 H2O2 的机制需要澄清.
研究的目的:
- 阐明在 EcBfr 铁氧化酶中心用 O2 和 H2O2 氧化铁的机械细节.
- 在体内确定 EcBfr 的作用,特别是铁封存与过氧化物排毒的作用.
主要方法:
- 紫外线/紫外线光谱学
- 电子偏磁共振 (EPR) 光谱学
- 莫斯巴乌尔光谱法是使用的.
- 用Fe2+对apo-EcBfr进行无氧加载,然后暴露于O2或H2O2.2.
主要成果:
- O2可逆地与二-Fe2+ FC结合,氧化两个Fe2+ 离子,形成一个释放的H2O2分子.
- 释放的H2O2会氧化另一种二-Fe2+FC,其氧化速度大约是O2的1000倍.
- 最初形成的Fe3+可以与H2O2反应,形成激素,但放松到不反应的形式.
结论:
- EcBfr利用一种机制,其中O2氧化产生H2O2,然后迅速氧化额外的铁.
- 在H2O2中介的快速铁氧化表明,EcBfr在体内H2O2排毒中起着主要的作用.
- 这些发现挑战了传统的观点,认为细菌铁素只是一种铁储存蛋白质.
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