Molecular mechanism of the reduction of cysteine sulfinic acid of peroxiredoxin to cysteine by mammalian sulfiredoxin
Molecular mechanism of the reduction of cysteine sulfinic acid of peroxiredoxin to cysteine by mammalian sulfiredoxin
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DOI：
10.1074/jbc.m511082200
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发表时间：
2006-05-19
影响因子：
4.8
通讯作者：
Rhee, Sue Goo
中科院分区：
文献类型：
--
作者：
Jeong, Woojin;Park, Sung Jun;Rhee, Sue Goo
在许多具有半胱氨酸亚磺酸（Cys-SO2 H）残基的蛋白质中，某些过氧化物氧还蛋白（Prxs）的亚磺酸形式在ATP存在下被硫氧还蛋白（Srx）选择性还原。所有Srx酶都含有保守的半胱氨酸残基。为了阐明Srx催化反应的机制，我们产生了Srx的各种突变体，并研究了它们与PrxI的相互作用，它们的ATP酶活性，以及它们减少亚磺酸PrxI的能力。我们的研究结果表明，三个表面暴露的氨基酸残基，对应于精氨酸（50），天冬氨酸（57），和天冬氨酸（79）的大鼠Srx，是关键的底物识别。PrxI的亚磺酸形式（而非还原形式）的存在诱导Srx的保守半胱氨酸摄取ATP的γ-磷酸，然后立即将磷酸转移到PrxI的亚磺酸部分，生成亚磺酸磷酰基酯（Prx-Cys-S（=O）OPO 32-）。该酯被巯基分子（RSH）如GSH、硫氧还蛋白和二硫苏糖醇还原裂解，产生二硫化物-S-一氧化物（Prx-Cys-S（=O）-S-R）。二硫化物-S-一氧化物通过三个硫醇当量的氧化进一步还原，以完成催化循环并再生Prx-Cys-SH。
Among many proteins with cysteine sulfinic acid (Cys-SO2H) residues, the sulfinic forms of certain peroxiredoxins (Prxs) are selectively reduced by sulfiredoxin (Srx) in the presence of ATP. All Srx enzymes contain a conserved cysteine residue. To elucidate the mechanism of the Srx-catalyzed reaction, we generated various mutants of Srx and examined their interaction with PrxI, their ATPase activity, and their ability to reduce sulfinic PrxI. Our results suggest that three surface-exposed amino acid residues, corresponding to Arg(50), Asp(57), and Asp(79) of rat Srx, are critical for substrate recognition. The presence of the sulfinic form (but not the reduced form) of PrxI induces the conserved cysteine of Srx to take the gamma-phosphate of ATP and then immediately transfers the phosphate to the sulfinic moiety of PrxI to generate a sulfinic acid phosphoryl ester (Prx-Cys-S(=O)OPO32-). This ester is reductively cleaved by a thiol molecule (RSH) such as GSH, thioredoxin, and dithiothreitol to produce a disulfide-S-monoxide (Prx-Cys-S(=O)-S-R). The disulfide-S-monoxide is further reduced through the oxidation of three thiol equivalents to complete the catalytic cycle and regenerate Prx-Cys-SH.