Deciphering the catalytic mechanism of redox-active glutaredoxins

破译氧化还原活性谷氧还蛋白的催化机制

• 批准号: 526346008
• 负责人: Professor Dr. Marcel Deponte
• 金额: --
• 依托单位: Fachrichtung Biochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/526346008?language=en
• 关键词: Deciphering; catalytic; mechanism; redox; active

Glutaredoxins (Grx) play central roles in redox and iron metabolism in pro- and eukaryotes under physiological and pathophysiological conditions. Most Grx belong to two major subfamilies, class I or canonical Grx, which are glutathione-dependent thiol:disulfide oxidoreductases, and class II Grx or Grx-like proteins, which are inactive in standard oxidoreductase assays but serve as iron sensors and are crucial for the glutathione-dependent delivery of iron-sulfur clusters. Despite significant recent advances, it is still predominantly unknown (i) how glutathionylated class I Grx are exactly reduced by reduced glutathione (GSH) during the reductive half-reaction, (ii) how non-glutathione disulfides are reduced during the oxidative half-reaction, (iii) why most class I Grx have a second or even third cysteine residue in the proximity of the catalytic cysteine, and (iv) if and how the activity of class I Grx is regulated. Here we want to address these open questions in two major work packages: 1. Deciphering the Grx-catalyzed reduction of glutathione disulfides • Where does the preference of Grx for GSH as the reducing substrate come from? • Do selected residues close to the reaction center have a regulatory role? 2. Deciphering the Grx-catalyzed reduction of non-glutathione disulfides • Do class I Grx reduce protein disulfides directly or do they activate GSH for reduction? • Do the redox potentials of protein disulfide substrates determine the mechanism? • Do alternative cysteines resolve trapped Grx disulfides in vivo?

谷氧还蛋白(GRX)在原核生物和真核生物的氧化还原和铁代谢中起着重要的生理和病理作用。大多数GRX属于两个主要的亚家族，I类或典型的GRX，它们是依赖谷胱甘肽的硫醇：二硫键氧化还原酶，以及II类GRX或GRX类蛋白，它们在标准的氧化还原酶分析中是不活跃的，但作为铁传感器，对依赖谷胱甘肽的铁-硫簇的运输至关重要。尽管最近取得了重大进展，但仍不清楚(I)还原型谷胱甘肽(GSH)是如何准确地还原谷胱甘肽(GSH)的I类GRX，(Ii)非谷胱甘肽二硫化物在氧化半反应中是如何被还原的，(Iii)为什么大多数I类GRX在催化半胱氨酸附近有第二个甚至第三个半胱氨酸残基，以及(Iv)I类GRX的活性是否以及如何受到调节。在这里，我们想通过两个主要的工作包来解决这些悬而未决的问题：1.破译GRX催化的谷胱甘肽二硫化物还原·GRX作为还原底物的偏好来自哪里？·靠近反应中心的部分残基是否具有调节作用？2.破译GRX催化的非谷胱甘肽二硫化物的还原过程·I类GRX是直接还原蛋白质二硫化物还是激活GSH进行还原？·蛋白质二硫化物的氧化还原电位决定机制吗？·替代半胱氨酸在体内分解捕获的GRX二硫化物吗？