Glutaredoxin catalysis requires two distinct glutathione interaction sites.
Glutaredoxin catalysis requires two distinct glutathione interaction sites.
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DOI：
10.1038/ncomms14835
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发表时间：
2017-04-04
影响因子：
16.6
通讯作者：
Deponte M
中科院分区：
文献类型：
--
作者：
Begas P;Liedgens L;Moseler A;Meyer AJ;Deponte M
谷氧还蛋白是细胞氧化还原稳态中的关键参与者，并发挥从谷胱甘肽依赖性催化到铁代谢的各种基本功能。尽管有许多动力学和结构研究，但在标准酶测定中有活性或无活性的谷氧还蛋白之间的确切结构-功能关系和机制差异迄今为止仍然难以捉摸。在这里，我们阐明的酶促机制表明，谷氧还蛋白需要两个不同的谷胱甘肽相互作用的网站，有效的氧化还原催化。第一个位点与谷胱甘肽化二硫化物底物的谷胱甘肽部分相互作用。第二个位点激活谷胱甘肽作为还原剂。我们建议，两个不同的谷胱甘肽相互作用位点的谷胱甘肽化二硫化物底物的有效还原的要求解释了不同的谷氧还蛋白亚家族以及硫氧还蛋白的偏离结构-功能关系，活动和底物偏好。我们的模型还为人工谷氧还蛋白，过渡态抑制剂和谷氧还蛋白偶联氧化还原传感器的设计或优化提供了重要的见解。谷氧还蛋白在氧化还原过程中具有重要作用。在这里，作者表明，谷胱甘肽的酶活性需要两个不同的谷胱甘肽相互作用位点，一个识别谷胱甘肽二硫化物底物和一个激活谷胱甘肽作为还原剂。
Glutaredoxins are key players in cellular redox homoeostasis and exert a variety of essential functions ranging from glutathione-dependent catalysis to iron metabolism. The exact structure–function relationships and mechanistic differences among glutaredoxins that are active or inactive in standard enzyme assays have so far remained elusive despite numerous kinetic and structural studies. Here, we elucidate the enzymatic mechanism showing that glutaredoxins require two distinct glutathione interaction sites for efficient redox catalysis. The first site interacts with the glutathione moiety of glutathionylated disulfide substrates. The second site activates glutathione as the reducing agent. We propose that the requirement of two distinct glutathione interaction sites for the efficient reduction of glutathionylated disulfide substrates explains the deviating structure–function relationships, activities and substrate preferences of different glutaredoxin subfamilies as well as thioredoxins. Our model also provides crucial insights for the design or optimization of artificial glutaredoxins, transition-state inhibitors and glutaredoxin-coupled redox sensors. Glutaredoxins have important roles in redox processes. Here the authors show that the enzymatic activity of glutaredoxins requires two distinct glutathione interactions sites, one recognizing the glutathione disulfide substrate and one activating glutathione as a reducing agent.