Expression and optimization of expression conditions of Tα1-TP5 fusion peptide in E.coli

Purpose To investigate the expression of Tα1-TP5 fusion peptide and optimization of the expression conditions.Methods The chemically synthesized Tα1-TP5 gene was fused with prokaryotic expression vector pGEX-4T-1 and transformed into E.coli BL21(DE3),subsequently induced by IPTG.SDS-PAGE electrophoresis and AlphaEase gel electrophoresis image analysis system were used to analyze the influence of culture medium,induction starting time,induction temperature,inducer concentration and induction time on the expression level of target protein.GST fusion protein was purified by GST sepharose and cut by recombinant enterokinase.Tα1-TP5 was identified by ESI-MS.Results When using TB as the medium and adding final concentration of 0.05 mmol/L of IPTG into the middle and late logarithmic phase of bacteria to induce for 5 h at 37 ℃,the expression of GST fusion protein was the highest,accounting for 35.8% of the bacterial total protein,and mainly in a soluble form.Identified by ESI-MS,the molecular weight of Tα1-TP5 was identical with theoretical value.Conclusion Tα1-TP5 has been successfully expressed in E.coli and the expression conditions of the GST fusion protein were optimized.