Thioredoxin Increases the Efficient and Soluble Expression of Insulin-Like Growth Factor-1 in E.coli

Abstract:

In order to overexpress soluble human insulin-like growth factor-1（IGF-1） in Escherichia coli and obtain a large number of bioactive proteins.A fusion gene containing trx and igf-1 was constructed via fusion of PCR technique and inserted into pET30a plasmid. Then the recombinant plasmid was transformed to E.coli strain C43（DE3） and a series of conditions optimization was carried out. After purification，target protein was identified by Western blot and determined for bioactivity. Trx-IGF-1 fusion protein was high expressed in soluble form in C43（DE3） after induction with 1mmol/L IPTG at 30 ℃ for 5 h. The recombinant protein reached a purity above 90% by using Ni2+ affinity chromatography and showed a strong antigenic ability by Western blot. The biological activity assay revealed that the fusion protein Trx-IGF-1 could significantly promote the proliferation and cell cycle progression of NIH3T3 cells. The carrier protein Trx can be used to realize the high-level soluble expression of bioactive IGF-1 in E.coli，which provide an evidence for the soluble expression of foreign proteins in E. coli.