Regulation of the OxyR transcription factor by hydrogen peroxide and the cellular thiol -: disulfide status
Regulation of the OxyR transcription factor by hydrogen peroxide and the cellular thiol -: disulfide status
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DOI：
10.1073/pnas.96.11.6161
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发表时间：
1999-05-25
影响因子：
11.1
通讯作者：
Storz, G
中科院分区：
文献类型：
--
作者：
Åslund, F;Zheng, M;Storz, G
大肠杆菌转录因子 OxyR 通过分子内二硫键的形成而被激活，随后通过二硫键的酶还原而失活。在这里，我们表明 OxyR 可以通过两种可能的途径激活。在细胞二硫键还原系统有缺陷的突变体中，在没有添加氧化剂的情况下，OxyR 通过硫醇二硫键氧化还原状态的变化而被组成型激活。在野生型细胞中，OxyR 被过氧化氢激活。通过监测体内和体外暴露于过氧化氢后OxyR二硫键的存在，我们还表明低浓度过氧化氢氧化OxyR的动力学明显快于OxyR还原的动力学，从而允许在整体还原环境中瞬时激活。我们认为 OxyR 体内的活性是由过氧化氢水平和细胞氧化还原环境之间的平衡决定的。
The Escherichia coli transcription factor OxyR is activated by the formation of an intramolecular disulfide bond and subsequently is deactivated by enzymatic reduction of the disulfide bond. Here we show that OxyR can be activated by two possible pathways. In mutants defective in the cellular disulfide-reducing systems, OxyR is constitutively activated by a change in the thiol-disulfide redox status in the absence of added oxidants. In wild-type cells, OxyR is activated by hydrogen peroxide. By monitoring the presence of the OxyR disulfide bond after exposure to hydrogen peroxide in vivo and in vitro, we also show that the kinetics of OxyR oxidation by low concentrations of hydrogen peroxide is significantly faster than the kinetics of OxyR reduction, allowing for transient activation in an overall reducing environment. We propose that the activity of OxyR in vivo is determined by the balance between hydrogen peroxide levels and the cellular redox environment.