Heterologous expression of pediocin/papA in Bacillus subtilis

Listeria monocytogenes is a food-borne pathogen. Pediocin is a group II alpha bacteriocin with anti-listeria activity that is naturally produced by Pediococcus acidilactic and Lactobacillus plantarum. The pedA/papA gene encodes pediocin/plantaricin. In native hosts, the expression and secretion of active PedA/PapA protein rely on the accessory protein PedC/PapC and ABC transporter PedD/PapD on the same operon. The excretion machines were also necessary for pediocin protein expression in heterologous hosts of E. coli, Lactobacillus lactis, and Corynebacterium glutamicum. In this study, two vectors carrying the codon sequence of the mature PapA peptide were constructed, one with and one without a His tag. Both fragments were inserted into the plasmid pHT43 and transformed into Bacillus subtilis WB800N. The strains were induced with IPTG to secrete the fused proteins PA1 and PA2. Supernatants from both recombinant strains can inhibit Listeria monocytogenes ATCC54003 directly. The fused protein possesses inhibition activity as a whole dispense with removal of the leading peptide. This is the first report of active pediocin/PapA expression without the assistance of PedCD/PapCD in heterogeneous hosts. In addition, the PA1 protein can be purified by nickel-nitrilotriacetic acid (Ni-NTA) metal affinity chromatography.

Automated summary

Listeria monocytogenes is a food-borne pathogen. Pediocin, a bacteriocin naturally produced by Pediococcus acidilacticus and Lactobacillus plantarum, has anti-listeria activity. In this study, researchers were able to express active pediocin/PapA in heterologous hosts without the assistance of accessory proteins. They also successfully purified the PA1 protein.