铁蛋白DrfE对耐辐射异常球菌抗氧化酶活性的影响

Effect of Ferritin Drf E on Antioxidant Enzyme Activity in Deinococcus radiodurans

为研究耐辐射异常球菌(Deinococcus radiodurans)中drf E编码的铁蛋白Drf E的功能,通过基因回补试验构建drf E基因的回补菌株(pdrf E∷Δ),对野生型WT、突变株Δdrf E及回补菌株pdrf E∷Δ进行不同浓度H_2O_2和Na Cl胁迫,分别测定野生型WT、突变株Δdrf E和回补菌株pdrf E∷Δ体内Fe2+含量及抗氧化酶类活性。结果显示,drf E基因缺失导致菌株对氧化和盐胁迫敏感,该基因的回补能够恢复菌株对氧化和盐胁迫的抗性。drf E基因缺失导致耐辐射异常球菌体内Fe2+浓度由232μmol/L增加至293μmol/L;80 mmol/L H_2O_2处理30 min后,突变株Δdrf E的CAT活性下降32.74%,SOD下降41.3%。以上结果表明Drf E蛋白可能参与耐辐射异常球菌铁代谢途径,并且在细胞抗氧化体系中发挥重要作用。

To investigate the function of the ferritin DrfE encoded by gene drfE in Deinococcus radiodurans, we constructed the complemented strain pdrfE ：： A, and compared the stress resistances of the wild-type WT, mutant ztdrfE and complemented strain pdrfE ： ： A under different doses of hydrogen peroxide （ H2O2 ） and NaC1. Also, the Fee＋concentration andantioxidant enzyme activities of three strains were measured under oxidative stress. The results showed that the deletion of gene drfE led the strain to be more sensitive to oxidative and high- salt stresses and the complementation of gene drfE restored the resistance of the strain to oxidative and salt stress. Furthermore, the deletion of drfE resulted in the Fe^2＋ concentration in D. radiodurans cell increased from 232 μmol/L to 293 μmol/L in vivo. After treated with 80 mmol.L H=O2 for 30 min, the CAT and SOD activities of the mutant ΔdrfE decreased by 32.74% and 41.3%, respectively, than that of wild-type. The above findings implied that the ferritin DrfE might be involved in iron metabolic pathway of D. radiodurans and played a key role in antioxidant system.