通过DNA介导的DPS,A细菌酸的氧化
Anna R Arnold1, Andy Zhou1, Jacqueline K Barton1
1Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
Journal of the American Chemical Society
|August 30, 2016
概括
Dps蛋白质可以保护细菌DNA免受氧化应激. 由关氨酸和氨酸促进的DNA电荷传输能够有效氧化Dps铁位点,这对细菌的生存至关重要.
科学领域:
- 生物化学
- 分子生物学
- 光谱学
背景情况:
- Dps蛋白是对抗氧化应激的DNA保护所必需的细菌费里丁,影响细菌的生存和毒性.
- Dps铁位点的氧化可以通过直接接触或通过DNA电荷传输 (CT) 发生,这种机制涉及通过DNA基对π传输的电子和孔.
研究的目的:
- 用光谱学方法研究含铁的 Dps 蛋白质的 DNA 中介氧化机制.
- 阐明DNA基和蛋白质残留在Dps氧化过程中促进电子转移的作用.
主要方法:
- 使用X波段电子磁共振 (EPR) 光谱来监测Dps氧化.
- 通过插入光氧化剂和闪灭技术诱导DNA光氧化.
- 实验使用了合成DNA聚合物,poly ((dGdC) 2和poly ((dAdT) 2以及W52A Dps突变物.
主要成果:
- 用多基基2对Dps进行辐射,结果在g=4.3时产生EPR信号,表明单核高基基基位的形成.
- 用poly ((dAdT) 2替代显著降低了Dps氧化产量,这表明瓜基中间体促进了该过程.
- 一种W52A Dps突变在形成Fe(III) 信号方面表现出明显的缺陷,这意味着基残留物W52作为电子转移中间体.
结论:
- 特别是涉及瓜的DNA电荷传输是氧化DPS铁位点的有效机制.
- 在DNA介导的Dps氧化过程中,保存的基 W52作为关键的电子转移跳跃中间体.
- 在体外,W52A突变会损害Dps的功能,并在体内氧化应激下降低细菌的存活率.
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