重组K88黏附素亚单位蛋白在大肠杆菌中的诱导表达

采用响应面分析方法,对肠毒素大肠杆菌(EnterotoxigenicEscherichiacoli)K88黏附素亚单位重组蛋白FaeG诱导表达的主要影响因素进行了优化研究。响应面分析结果表明:不同的诱导时机、IPTG浓度及诱导时间对目的蛋白表达量均有显著影响(P<0.01),三因素之间的交互作用对目的蛋白表达量也有极显著的影响(P<0.01)。通过进一步的模拟优化,得到了最佳诱导表达条件为培养BL21(K88ac)重组菌株2.5h后,加入IPTG至终浓度0.8mmol/L,37℃诱导培养5h。采用以上参数进行验证实验,得到目的蛋白在全菌蛋白中的表达含量为35.4%;与单次单因子法得到的最佳表达条件下的表达量(27.5%)相比,提高了28.7%。采用响应面分析法可以确定IPTG的诱导时机、诱导浓度及诱导时间等多个因素对重组蛋白在大肠杆菌中表达的最佳作用条件,有利于提高目的蛋白的表达量。

Optimization of Expression of Recombinant K88 Fimbrial Subunit Protein in Escherichia coli

Response surface analysis(RSA) was applied to optimize the main parameters on expression of recombinant K88 subunit protein FaeG in Enterotoxigenic Escherichia coli. The results showed that three factors including induction starting time, IPTG concentration and inducing time,and their interactions all had significant effects on expression of recombinant FaeG(P <0.01). Further simulated optimization revealed that the percentage of recombinant FaeG protein in complete bacterial protein was 35.4% by adding IPTG 0.8 mmol/L and inducing 5 h after 2.5 h culture, improved by 28.7% compared with the production(27.5%) obtained under the conditions optimized by one-variable-at-a-time. It is concluded that RSA is an effective method to optimize the parameters such as induction starting time, IPTG concentration and inducing time in improving the expression of recombinant protein in E.coli.