Soluble overexpression,high-level production and purification of receptor binding domain of human VEGF8-109 in E. coli

The high-yield production of vascular endothelial growth factor (VEGF), as a major therapeutic target in pathological angiogenesis and diabetic wound healing, provides critical advantages for in vitro studies. In the present study, to improve the soluble production of human VEGF_8–109 (receptor-binding domain (RBD) of VEGF or VEGF RBD), at first VEGF _8-109 encoded gene was expressed in SHuffle T7 E. coli. Moreover, in two steps, the protein production was optimized based on Taguchi design, by evaluating optimal levels of various induction parameters, such as cell density in induction time, temperature, inducer concentration, and media components. The results indicated that the highest amount of the protein was achieved in TB medium containing glycerol 6 g L⁻¹, peptone to yeast extract ratio 1:1, ethanol 3% and MgSO₄ 4 g L⁻¹, under inducing with 0.05 mM IPTG in OD₆₀₀ of 0.7 at 24 °C for 22 h. The bioactivity of the purified protein was confirmed by cell proliferation assay. Finally, bench-scale production of VEGF_8–109 was performed under the optimum conditions and resulted in 182 mg of soluble VEGF_8–109 expressed per liter. Totally, our results can be considered as a basis for economical production of the recombinant VEGF in future.