Heterologous expression of the novel α-helical hybrid peptide PR-FO in Bacillus subtilis

PR-FO is a novel α-helical hybrid antimicrobial peptide (AMP) with strong antimicrobial activities and high stability, and the potential to develop into a new generation of antimicrobial agents. In this study, the encoded gene sequence of SMT3-PR-FO was designed and transformed into B. subtilis WB800N. Fusion proteins with concentrations of 16 mg L−1 (SPamyQ) and 23 mg L−1 (SPsacB) were obtained after purification by a Ni–NTA resin column. A total of 3 mg (SPamyQ) and 4 mg (SPsacB) of PR-FO with a purity of 90% was obtained from 1 L fermentation cultures. Recombinant PR-FO exhibited high inhibition activities against both gram-negative bacteria and gram-positive bacteria, and low haemolytic activity against human red blood cells. These results indicated that the rSMT3-PR-FO could be expressed under the guidance of SPamyQ and SPsacB, and the maltose-induced expression strategy might be a safe and efficient method for the soluble peptides production in B. subtilis.