RESUMEN
Objective:To produce rhBMP-4 with bioactivity in E.coli. Methods: The full-length human BMP-4 gene was mutated by PCR without changes in amino acid sequence, then the synthesized gene was cloned into plasmid pET-3c, transducted into BL21(DE)plysS, and induced by adding IPTG to a final concentration of 1.0 mmol/L. The protein product was purified using ion-exchange chromatography method and then renaturated, bioactivity was checked by C2C12 differentiation in vitro and mouse ectopic bone formation in vivo. Results: A 438 bp gene fragment encoding mature peptide of hBMP-4 was cloned , the protein product was mostly in the form of inclusion body, after renaturation, the engineering protein shows better bioactivity. Conclusion:The mutant strategy can enhance the expression of bioactive rhBMP-4 in E.coli expression system.