Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, 310029 Hangzhou, China.
Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, 310029 Hangzhou, China.
Biochem Biophys Res Commun. 2014 Jul 18;450(1):575-80. doi: 10.1016/j.bbrc.2014.06.015. Epub 2014 Jun 10.
Response and defense systems against reactive oxygen species (ROS) contribute to the remarkable resistance of Deinococcus radiodurans to oxidative stress induced by oxidants or radiation. However, mechanisms involved in ROS response and defense systems of D. radiodurans are not well understood. Fur family proteins are important in ROS response. Only a single Fur homolog is predicted by sequence similarity in the current D. radiodurans genome database. Our bioinformatics analysis demonstrated an additional guanine nucleotide in the genome of D. radiodurans that is not in the database, leading to the discovery of another Fur homolog DrPerR. Gene disruption mutant of DrPerR showed enhanced resistance to hydrogen peroxide (H2O2) and increased catalase activity in cell extracts. Real-time PCR results indicated that DrPerR functions as a repressor of the catalase gene katE. Meanwhile, derepression of dps (DNA-binding proteins from starved cells) gene under H2O2 stress by DrPerR point to its regulatory role in metal ions hemostasis. Thus, DrPerR might function as a Fur homolog protein which is involved in ROS response and defense. These results help clarify the complicated regulatory network that responds to ROS stress in D. radiodurans.
应对活性氧（ROS）的反应和防御系统有助于耐辐射球菌对氧化剂或辐射引起的氧化应激的显著抵抗。然而，耐辐射球菌的 ROS 反应和防御系统中涉及的机制还不是很清楚。Fur 家族蛋白在 ROS 反应中很重要。在当前的耐辐射球菌基因组数据库中，通过序列相似性预测只有一个 Fur 同源物。我们的生物信息学分析表明，耐辐射球菌的基因组中存在一个数据库中没有的额外的鸟嘌呤核苷酸，从而发现了另一个 Fur 同源物 DrPerR。DrPerR 的基因敲除突变体对过氧化氢（H2O2）的抗性增强，细胞提取物中的过氧化氢酶活性增加。实时 PCR 结果表明，DrPerR 作为过氧化氢酶基因 katE 的阻遏物发挥作用。同时，DrPerR 在 H2O2 胁迫下对 dps（饥饿细胞中的 DNA 结合蛋白）基因的去阻遏表明其在金属离子止血中的调节作用。因此，DrPerR 可能作为一种 Fur 同源蛋白参与 ROS 反应和防御。这些结果有助于阐明耐辐射球菌中应对 ROS 应激的复杂调控网络。
