利用 pET-28a(+)质粒将来源于耐辐射异常球菌(Deinococcus radiodurans)R1的 irrE 基因在大肠杆菌(Escherichia coli)BL21(DE3)中进行异源表达,在IPTG终浓度2,mmol/L、诱导温度37,℃、诱导培养6,h条件下进行了蛋白诱导。进一步考察 IrrE 异源表达对大肠杆菌生长性能和耐受能力的影响,结果表明:IrrE 的表达能够提高大肠杆菌正常条件下的生长速率和最终生物量;同时,能够不同程度提高大肠杆菌在压力冲击下的存活能力,其中,高渗条件下存活能力的提高最为明显。而重组菌株在压力冲击下的生长速率和最终生物量均明显高于对照菌株。这说明 IrrE在提高大肠杆菌的压力耐受性方面表现出良好的效果。
The heterologous expression of irrE,from Deinococcus radiodurans R1,in E. coli BL21(DE3)was carried out using the vector pET-28a(+). The optimal protein expression conditions of IrrE were as follows.The final concentration of IPTG was 2,mmol/L,and the induction temperature and time were 37,℃and 6,h,respectively. The influence of IrrE on cell growth and tolerance was further investigated. The results indicated that IrrE could enhance the growth rate and produce more final biomass of Escherichia coli under normal conditions,and improve the survival ability of the cell under stress shock to different extent,especially the tolerance to osmotic shock. The growth rate was higher and significantly more final biomasses of the recombinant strain containing pET-28a(+)-irrE under stress were found than in the control strain(harboring the empty vector pET-28a(+)). It can be concluded that the expression of IrrE could enhance the tolerance of E. coli to stress.