Li Ning, Luo Qixia, Jiang Yaoming, Wu Genfu, Gao Haichun
Environ Microbiol. 2014 Jun;16(6):1821-34. doi: 10.1111/1462-2920.12418.
Shewanella oneidensis, renowned for its remarkable respiratory abilities, inhabit redox-stratified environments prone to reactive oxygen species (ROS)formation. Two major oxidative stress regulators,analogues of OxyR and OhrR, specifically respond to H(2)O(2) and organic peroxides (OP), respectively, are encoded in the genome based on sequence comparison to well-studied models. Presumably, these analogues provide protection from ROS. An understanding of S. oneidensis OxyR has been established recently, which functions as both repressor and activator to mediate H(2)O(2)-induced oxidative stress. Here,we report the first study of elucidating molecular mechanisms underlying the S. oneidensis response to OP-induced oxidative stress. We show tha tS. oneidensis has OhrR, an OP stress regulator with two novel features. The sensing and responding residues of OhrR are not equally important for regulation and the regulator directly controls transcription of the SO1563 gene, in addition to the ohr gene which encodes the major OP scavenging protein. Importantly,we present evidence suggesting that the OxyR and OhrR regulons of S. oneidensis appear to be functionally intertwined as both OxyR and OhrR systems can sense and response to H(2)O(2) and OP agents.
奥奈达希瓦氏菌以其卓越的呼吸能力而闻名，它栖息于易于形成活性氧（ROS）的氧化还原分层环境中。基于与深入研究的模型进行序列比较，在其基因组中编码了两种主要的氧化应激调节因子，分别是OxyR和OhrR的类似物，它们分别对过氧化氢（H₂O₂）和有机过氧化物（OP）作出特异性反应。据推测，这些类似物可提供对ROS的保护作用。最近已经对奥奈达希瓦氏菌的OxyR有所了解，它作为阻遏物和激活剂发挥作用，介导H₂O₂诱导的氧化应激。在此，我们报告了第一项阐明奥奈达希瓦氏菌对OP诱导的氧化应激反应潜在分子机制的研究。我们发现奥奈达希瓦氏菌具有OhrR，这是一种具有两个新特征的OP应激调节因子。OhrR的传感和响应残基对调节的重要性并不相同，并且该调节因子除了控制编码主要OP清除蛋白的ohr基因外，还直接控制SO1563基因的转录。重要的是，我们提供的证据表明，奥奈达希瓦氏菌的OxyR和OhrR调控子在功能上似乎相互交织，因为OxyR和OhrR系统都能感知并响应H₂O₂和OP试剂。
