Expression of cecropin CMIV fusion protein in E. coli under T7 promoter

A synthetic gene coding for cecropin CMIV from Bombyx mori was cloned into plasmid pEZZ318 and fused to a DNA segment encoding the signal peptide of Staphylococcal protein A and IgG binding domain. The fusion gene was then subcloned into expression vector pET11c under the control of T7 promoter and expressed in E. coli. The fusion protein did not exhibit any antibacterial activity either in cell lysate or in medium. After cleavage from the fusion protein with CNBr the biological activity of recombinant cecropin CMIV was obtained.