Defensins are cationic antimicrobial peptides with a broad range of activities against bacteria and fungi. In the present study, the entire coding sequence of codon-optimized Bovine Neutrophil b-Defensin 2 (BNBD2) was designed and placed upstream of Trx coding sequence into the pET-48b (+) vector. Furthermore, the codon-optimized pelB signal sequences were also added to the upstream of BNBD2 for periplasmic localization. The periplasmic sorting of recombinant b-Defensin 2 was evaluated by osmotic shock and SDS–PAGE on the released proteins. Moreover, the expression of BNBD2-Trx fusion protein was confirmed by the Western blotting technique. Next, the purification of recombinant protein was achieved by Ni++ affinity chromatography. BNBD2 was also separated from Trx by chemical cleavage with formic acid. Finally, both of the antibacterial and antifungal activities of the purified protein were examined. Overall, the results indicated successful periplasmic production of BNBD2 protein, which showed antifungal activity against some of Aspergillus species as well as the antibacterial activity, expressed as successfully suppressed growth of Escherichia coli and Staphylococcus aureus. | Functional analysis of recombinant codon-optimized bovine neutrophil b-defensin
