Optimal purification conditions and identification of CTB-Aβ42 expression in Escherichia Coli

Purpose To explore the optimal conditions of the expression of fusion gene CTB-Aβ42 in E.Coli,and to purify the fusion protein CTB-Aβ42.Methods Induced expression of fusion protein CTB-Aβ42 in E.Coli of different temperatures,time and concentration of IPTG.The expression product was determined by SDS-PAGE and Western blot analysis.Fusion protein was purified by GST affinity chromatography.Results SDS-PAGE results showed that the molecular mass of fusion protein GST-CTB-Aβ42 is 45 kD as expected,and Western blot analysis indicated that anti-CTB antibody could react specifically against the fusion protein.Soluble expression reaches the highest level when it is induced by 0.1 mmol/L IPTG as final concentration for 2 h at 30 ℃.If induced by 0.1 mmol/L IPTG as final concentration for 4 h at 37 ℃,intracellular expression as inclusion bodies was the most efficient.Conclusion We optimized the conditions of the expression of fusion protein CTB-Aβ42 in E.Coli,and acquired purified fusion protein relatively.It provides a sufficient foundation for the further study on vaccine against Alzheimer disease.