Abstract: E17G， a genetically modified antimicrobial protein， has high antimicrobial activities against bacteria. To reduce the antibacterial activity lethal to the Escherichia coli host cells during its expression， the E17G gene was cloned into prokaryotic expression vector pGEX6P1 to generate the fusion expression plasmid pGEX6P1E17G(GSTE17G fusion). The GSTE17G fusion protein was expressed in E. coli BL21 induced by IPTG and purified by GST affinity chromatography. GSTE17G fusion protein was detected by SDSPAGE and Western blotting， indicating successful expression of GSTE17G protein in E. coli. This study provides the basis for further analysis of the biological activity of the E17G protein.

Key words: lysin, E. coli, fusion expression, purification