耐辐射球菌pprI在大肠杆菌中表达增强细胞抗氧化能力的研究

将耐辐射球菌(Deinococcus radiodurans)与DNA修复有关的开关基因—pprI通过穿梭质粒pRADZ3导入大肠杆菌TG1中，使其在正常培养条件下(不需诱导剂)表达PprI蛋白，并通过Western blot证实该基因在TG1中可稳定表达。与转化了空白质粒pRADZ3 TG1对照，观察了改造后的两种大肠杆菌在有H2O2氧化压力下的存活率和大肠杆菌中两种过氧化氢酶（KatE, KatG）的活性表达差异。结果表明，无论在指数生长期还是稳定生长期，能表达PprI蛋白的大肠杆菌比对照的存活率要高出10％左右；非变性电泳结果表明，耐辐射球菌pprI 在大肠杆菌中的表达使得KatE活性在指数生长期与稳定生长期分别增加1.5～2倍和2.5～3倍。证明耐辐射球菌pprI 在大肠杆菌中的表达能够增强细胞抗氧化能力。

Study on Enhances of The Antioxidation in Escherichia coli by Expression of Deinococcus radiodurans pprI

The Deinococcus radiodurnas pprI, a switch gene responsible for DNA repair, was transformed to E.coli via a shuttle plasmid pRADZ3 and a recombinant fusion PprI protein was expressed in normal growth condition without induction. The stable expression of PprI protein in E.coli TG1 was confirmed by Western blot. Empty plasmid pRADZ3 was transformed to E.coli TG1 as control. The viabilities under H 2O 2 oxidative stress and the differences in catalases(KatE, KatG) activities of these two reconstructed E.coli TG1 were observed. The results showed that either in exponential phase or stationary phase, the expression of PprI protein in E.coli TG1 can enhance the viabilities, compared with the relative control; The results obtained from the Native-PAGE indicates that the expression of pprI in E.coli TG1 can enhance the enzymatic activity.It is concluded that the expression of D. radiodurans pprI can enhance the antioxidation in E.coli.