Expression and Antibacterial Activity of Stx Phage Endolysin of Escherichia coli O157

To investigate the antibacterial activity of Stx phage endolysin of Escherichia coli O157 toward Enterohemorrhagic Escherichia coli(EHEC),LysEC1,endolysin of Stx2 phage from Escherichia coli O157 Min27,was successfully constructed,purified and characterized,and then antibacterial activity and lysis spectrum of LysEC1 were analyzed.The complete endolysin gene(R gene) of Stx2 phage Min27 was amplified by PCR,and targeted fragment was cloned into expression Escherichia coli vector pET28a.Recombinant vector pET-28a(+)-LysEC1 was transformed into BL21.The results showed that exogenous protein was highly expressed in BL21,which accounted for about 34% of total protein.After purification with His-trapTM column,the recombinant LysEC1 was obtained with more than 97% of purity.Lysis test in vitro showed that LysEC1 exerted efficient lysis activity to several E.coli O157 strains.Those results were the foundation for the future application of LysEC1 in the treatment of EHEC infection.