Prokaryotic expression of antimicrobial ovine β-defensin-1 in Escherichia coli

Ovine beta-defensin-1 (sBD-1) is a small, cationic peptide, with three canonical cysteine disulfide intramolecular bonds. It can inhibit the growth of Gram-positive and Gram-negative bacteria, yeast and fungi. We isolated sBD-1 by RT-PCR of small intestinal cDNA. The open reading frame of the cDNA was 192 bp, which codes 64 amino acids, and the mature peptide of the cDNA was 114bp, which encodes 38 amino acids. In order to understand their antimicrobial activities, the pre-peptide sBD-1 and the mature peptide of sBD-1 were studied. The two proteins were expressed in Escherichia coli. The fusion proteins were purified and digested by enterokinase. The digestion products showed that the mature peptide can inhibit the growth of E. coli and P. aeruginosa. It will be valuable to produce sBD-1 and other defensins for veterinary medical research on antibiotic treatment in ovine production.