Glutathione Peroxidase 7 Utilizes Hydrogen Peroxide Generated by Ero1α to Promote Oxidative Protein Folding
Glutathione Peroxidase 7 Utilizes Hydrogen Peroxide Generated by Ero1α to Promote Oxidative Protein Folding
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谷胱甘肽过氧化物酶 7 利用 Ero1 α 产生的过氧化氢促进氧化蛋白质折叠
DOI：
10.1089/ars.2013.5236
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发表时间：
2014-02-01
影响因子：
6.6
通讯作者：
Wang, Chih-chen
中科院分区：
文献类型：
--
作者：
Wang, Lei;Zhang, Lihui;Wang, Chih-chen
目的：Ero1 黄素蛋白催化内质网 (ER) 中的氧化折叠，消耗氧气并产生过氧化氢 (H2O2)。内质网定位的谷胱甘肽过氧化物酶 7 (GPx7) 在体外显示出蛋白质二硫键异构酶 (PDI) 依赖性过氧化物酶活性。我们的工作旨在确定 GPx7 在 Ero1/PDI 氧化折叠途径中的生理作用并剖析 GPx7 的反应机制。结果：我们的数据表明，GPx7 可以利用 Ero1 产生的 H2O2 在体外和体内加速底物的氧化折叠。 H2O2 将 GPx7 的 Cys57 氧化为次磺酸，次磺酸可被 Cys86 拆分，形成分子内二硫键。 GPx7的二硫键形式和次磺酸形式均可氧化PDI以催化氧化折叠。 GPx7 更喜欢与 PDI 的 a 结构域相互作用，PDI 的两个氧化还原活性位点之间的分子内合作增加了 Ero1/GPx7/PDI 三联体的活性。创新：我们的体外和体内证据提供了关于细胞如何消耗潜在有害的 H2O2 同时通过 Ero1/GPx7/PDI 三联体优化氧化蛋白折叠的机制见解。 Cys57 可以通过两种方式促进 PDI 氧化，而 Cys86 则作为一种新型非经典解析半胱氨酸出现。结论：GPx7在早期分泌室中直接利用Ero1产生的H2O2，促进氧化蛋白折叠。因此，Ero1/GPx7/PDI 三联体以单个 O-2 分子为代价生成两个二硫键和两个 H2O 分子。
Aims: Ero1 flavoproteins catalyze oxidative folding in the endoplasmic reticulum (ER), consuming oxygen and generating hydrogen peroxide (H2O2). The ER-localized glutathione peroxidase 7 (GPx7) shows protein disulfide isomerase (PDI)-dependent peroxidase activity in vitro. Our work aims at identifying the physiological role of GPx7 in the Ero1/PDI oxidative folding pathway and at dissecting the reaction mechanisms of GPx7. Results: Our data show that GPx7 can utilize Ero1-produced H2O2 to accelerate oxidative folding of substrates both in vitro and in vivo. H2O2 oxidizes Cys57 of GPx7 to sulfenic acid, which can be resolved by Cys86 to form an intramolecular disulfide bond. Both the disulfide form and sulfenic acid form of GPx7 can oxidize PDI for catalyzing oxidative folding. GPx7 prefers to interact with the a domain of PDI, and intramolecular cooperation between the two redox-active sites of PDI increases the activity of the Ero1/GPx7/PDI triad. Innovation: Our in vitro and in vivo evidence provides mechanistic insights into how cells consume potentially harmful H2O2 while optimizing oxidative protein folding via the Ero1/GPx7/PDI triad. Cys57 can promote PDI oxidation in two ways, and Cys86 emerges as a novel noncanonical resolving cysteine. Conclusion: GPx7 promotes oxidative protein folding, directly utilizing Ero1-generated H2O2 in the early secretory compartment. Thus, the Ero1/GPx7/PDI triad generates two disulfide bonds and two H2O molecules at the expense of a single O-2 molecule.