Expression and purification of antimicrobial peptide AP2 using SUMO fusion partner technology in Escherichia coli

Apidaecins (APs) are proline-rich antimicrobial peptides that were isolated from Apismelifera. APs possess broad-spectrum activities against Gram-negative bacteria and exhibit immune-modulatory functions. AP2, an artificial mutant AP peptide with improved activities, was expressed in Escherichia coli expression system using small ubiquitin-related modifier (SUMO) fusion technology and ZYM-5052 auto-induction medium. Approximately 23 mg of recombinant fusion protein smt3AP2 was purified per litre cultivated medium. After SUMO protease (Ulp) cleavage of smt3AP2, recombinant AP2 was further purified by affinity and cation exchange chromatography. The pure recombinant AP2 with calculated value of 2 center dot 23 kDa reached a yield of 2 center dot 7 mg l(-1) and exhibited powerful antibacterial activity towards E. coli K88 with minimum inhibitory concentration at 5 mu g ml(-1). The recombinant fusion strategy presented in this study allows convenient high yield and easy purification of recombinant AP2.