Partridge Jonathan D, Poole Robert K, Green Jeffrey
Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, UK.
Microbiology (Reading). 2007 May;153(Pt 5):1499-1509. doi: 10.1099/mic.0.2006/004838-0.
The Escherichia coli FNR protein is an oxygen-responsive global transcription factor, and OxyR is a key regulator of the peroxide stress response. Here both FNR and OxyR are shown to regulate expression of the E. coli yhjA gene. The yhjA gene encodes a predicted cytochrome c peroxidase, a bacterial haem-containing protein involved in the peroxide stress response through its ability to convert hydrogen peroxide to water. It is shown that the yhjA gene of E. coli possesses a class II FNR site and an OxyR site upstream of the yhjA transcript start. Expression of yhjA was found to be dependent on this unusual combination of FNR and OxyR under conditions of oxygen starvation. Phenotypic analysis of the yhjA mutant revealed increased sensitivity to exogenous hydrogen peroxide and organic peroxides during growth under anaerobic conditions, consistent with the observed regulation and predicted function of the yhjA gene product.
大肠杆菌FNR蛋白是一种氧响应性全局转录因子，而OxyR是过氧化物应激反应的关键调节因子。本文表明，FNR和OxyR均可调节大肠杆菌yhjA基因的表达。yhjA基因编码一种预测的细胞色素c过氧化物酶，这是一种含细菌血红素的蛋白质，通过将过氧化氢转化为水的能力参与过氧化物应激反应。研究表明，大肠杆菌的yhjA基因在yhjA转录起始位点上游具有一个II类FNR位点和一个OxyR位点。发现在氧饥饿条件下，yhjA的表达依赖于FNR和OxyR这种不同寻常的组合。对yhjA突变体的表型分析表明，在厌氧条件下生长时，其对外源过氧化氢和有机过氧化物的敏感性增加，这与观察到的调节作用以及yhjA基因产物的预测功能一致。
