Crystal structure of reduced and of oxidized peroxiredoxin IV enzyme reveals a stable oxidized decamer and a non-disulfide-bonded intermediate in the catalytic cycle.
Crystal structure of reduced and of oxidized peroxiredoxin IV enzyme reveals a stable oxidized decamer and a non-disulfide-bonded intermediate in the catalytic cycle.
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DOI：
10.1074/jbc.m111.298810
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发表时间：
2011-12-09
期刊：
影响因子：
--
通讯作者：
Bulleid NJ
中科院分区：
文献类型：
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作者：
Cao Z;Tavender TJ;Roszak AW;Cogdell RJ;Bulleid NJ
背景：过氧化还原蛋白 IV 代谢内质网衍生的过氧化氢。结果：过氧化还原蛋白 IV 结构揭示了酶循环中异常稳定的十聚体和磺酰化中间体。结论：过氧化还原蛋白 IV 的酶促循环涉及活性位点的不稳定，随后形成稳定的二硫键十聚体。意义：需要阐明过氧化还原蛋白的结构，以了解它们在氧化应激过程中如何发挥作用。过氧化还原蛋白 IV (PrxIV) 是一种内质网定位酶，可代谢内质网氧化酶 1 (Ero1) 产生的过氧化氢。它已被证明在二硫键从头形成、氧化蛋白质二硫键异构酶家族成员中发挥作用，并且是典型的 2-Cys 过氧化还原蛋白家族的成员。我们已经确定了人 PrxIV 的还原和二硫键以及解析半胱氨酸突变体的晶体结构。我们表明，PrxIV 具有与其他典型 2-Cys 过氧化还原蛋白类似的结构，并且在过氧化残基和溶解半胱氨酸残基之间形成二硫键后，经历从完全折叠形式到局部未折叠形式的构象变化。与其他哺乳动物典型的 2-Cys 过氧化还原蛋白不同，我们发现人 PrxIV 即使在二硫键状态下也会形成稳定的十聚体结构。此外，解析半胱氨酸突变体的结构揭示了反应循环中采用局部未折叠构象的中间体。有趣的是，晶体结构中的过氧化半胱氨酸是磺酰化的，而不是亚磺酰化或磺酰化的。此外，在与高浓度过氧化氢一起孵育后，解析半胱氨酸突变体中的过氧化半胱氨酸能够抵抗过度氧化。这些结果突出了 PrxIV 的一些独特性质，并表明完全折叠和局部未折叠形式之间的平衡有利于过氧化半胱氨酸残基磺酰化时的局部未折叠构象。
Background: Peroxiredoxin IV metabolizes endoplasmic reticulum-derived hydrogen peroxide. Results: Peroxiredoxin IV structures reveal an unusually stable decamer and a sulfenylated intermediate in the enzymatic cycle. Conclusion: The enzymatic cycle of peroxiredoxin IV involves destabilization of the active site followed by formation of a stable disulfide-bonded decamer. Significance: Elucidating peroxiredoxin structures is required to understand how they function during oxidative stress. Peroxiredoxin IV (PrxIV) is an endoplasmic reticulum-localized enzyme that metabolizes the hydrogen peroxide produced by endoplasmic reticulum oxidase 1 (Ero1). It has been shown to play a role in de novo disulfide formation, oxidizing members of the protein disulfide isomerase family of enzymes, and is a member of the typical 2-Cys peroxiredoxin family. We have determined the crystal structure of both reduced and disulfide-bonded, as well as a resolving cysteine mutant of human PrxIV. We show that PrxIV has a similar structure to other typical 2-Cys peroxiredoxins and undergoes a conformational change from a fully folded to a locally unfolded form following the formation of a disulfide between the peroxidatic and resolving cysteine residues. Unlike other mammalian typical 2-Cys peroxiredoxins, we show that human PrxIV forms a stable decameric structure even in its disulfide-bonded state. In addition, the structure of a resolving cysteine mutant reveals an intermediate in the reaction cycle that adopts the locally unfolded conformation. Interestingly the peroxidatic cysteine in the crystal structure is sulfenylated rather than sulfinylated or sulfonylated. In addition, the peroxidatic cysteine in the resolving cysteine mutant is resistant to hyper-oxidation following incubation with high concentrations of hydrogen peroxide. These results highlight some unique properties of PrxIV and suggest that the equilibrium between the fully folded and locally unfolded forms favors the locally unfolded conformation upon sulfenylation of the peroxidatic cysteine residue.