单醇谷氨素可以结合线性[Fe3S4]+和[Fe4S4]2+集群,除了[Fe2S2]2+集群:光谱特征和功能影响
Bo Zhang1, Sibali Bandyopadhyay, Priyanka Shakamuri
1Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia 30602, United States.
Journal of the American Chemical Society
|September 17, 2013
概括
甲基线粒体的Saccharomyces cerevisiae 5 (Grx5) 主要包含一个线性[Fe3S4](+) 群,而不是以前认为的[Fe2S2](2+) 群. 这一发现影响了对铁硫集群贩运和蛋白质成熟的理解.
科学领域:
- 生物化学 生物化学
- 生物有机化学 生物有机化学
- 分子生物学分子生物学
背景情况:
- 甲基核糖素5 (Grx5) 是一个关键的单醇糖素,参与铁硫集群贩运.
- CGFS活性部位序列保留在单醇谷氨毒素中,这表明在处理铁硫中具有共同的功能.
- 之前的研究经常将单甲醇Grxs中的铁硫含量解释为[Fe2S2](2+) .
研究的目的:
- 为了描述重组Saccharomyces cerevisiae Grx5.5.的铁硫组成.
- 调查结合Grx5.5的铁硫集群的结构和电子特性.
- 为了澄清Grx5在铁硫集群贩运和蛋白质成熟中的作用.
主要方法:
- 在有氧和无氧条件下净化复合的S. cerevisiae Grx5.
- 光谱表征包括紫外线吸收/CD/MCD,EPR,Mössbauer和共振拉曼光谱.
- 突变和分析研究来评估集群结合.
主要成果:
- 再组合Grx5主要含有线性[Fe3S4](+) 集群,当与谷氨进行有氧净化或无氧复制时.
- 谱光学数据显示了一个体S = 5/2线性[Fe3S4](+) 集群,类似于合成类似物和紫色酸酶.
- 在没有谷氨的情况下,Grx5形成了一个二元体,其中有一个[Fe4S4](2+) 集群,能够在体外激活阿波阿康尼酶.
结论:
- 包括Grx5在内的单甲基Grxs中的铁硫含量在很大程度上被误解,以线性[Fe3S4](+) 为主.
- 在氧化应激下,Grx5在清理和回收线性[Fe3S4](+) 集群以及含有[Fe4S4](2+) 的蛋白质的成熟中发挥作用.
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