乳糖诱导胸腺融合肽Tα1-TP5在大肠杆菌中的表达

Expression of Tα1-TP5 fusion peptide in E.coli induced by lactose

目的研究用乳糖替代异丙基-β-D-硫代吡喃半乳糖苷(IPTG)作为诱导剂诱导胸腺融合肽Tα1-TP5表达,并优化诱导表达条件。方法在摇瓶发酵条件下,以乳糖作为诱导剂,SDS-PAGE电泳和AlphaEase凝胶电泳图像分析系统研究培养基组成、诱导剂浓度、诱导时机、诱导时间、诱导温度和诱导方式等条件对目的肽Tα1-TP5表达量的影响,并与IPTG诱导结果相比较。结果选用TB培养基,在菌体对数生长的中后期加入终浓度为1 g/L的乳糖,37℃诱导6 h,GST-Tα1-TP5融合蛋白的表达量约占菌体总蛋白的35%,且主要以可溶形式表达,与IPTG的诱导结果相同。分批流加乳糖4次和一次性加入乳糖诱导,融合蛋白表达量无明显差异。结论乳糖可以替代IPTG诱导胸腺融合肽Tα1-TP5的表达。

Purpose To study the use of lactose instead of IPTG as the inducer for the expression of recombinant thymosin 1-thymopentin fusion peptide（Tα1-TP5）,and to optimize the expression conditions.Methods Under the shake flask fermentation conditions,the influence of culture medium,inducer concentration,induction starting time,induction time,induction temperature and induction method on the expression level of target protein was analyzed by SDS-PAGE electrophoresis and AlphaEase gel electrophoresis image analysis system,and results were compared with those induced by IPTG.Results When using TB as the medium,adding final induction concentration of 1 g/L of lactose to the middle and late logarithmic phase of bacteria to induce for 6 h at 37 ℃,the GST-Tα1-TP5 fusion protein accounted for 35% of the bacterial total protein,mainly in a soluble form,and the expression level was the same as that induced by IPTG.The result of adding lactose once had no significant diffience compared with that of adding four times.Conclusion Lactose can be used as the inducer instead of IPTG for the expression of Tα1-TP5.