A putative amino acid transporter determines sensitivity to the two-peptide bacteriocin plantaricin JK

Abstract

Lactobacillus plantarum produces a number of antimicrobial peptides (bacteriocins) that mostly target closely related bacteria. Although bacteriocins are important for the ecology of these bacteria, very little is known about how the peptides target sensitive cells. In this work, a putative membrane protein receptor of the two-peptide bacteriocin plantaricin JK was identified by comparing Illumina sequence reads from plantaricin JK-resistant mutants to a crude assembly of the sensitive wild-type Weissella viridescens genome using the polymorphism discovery tool VAAL. Ten resistant mutants harbored altogether seven independent mutations in a gene encoding an APC superfamily protein with 12 transmembrane helices. The APC superfamily transporter thus is likely to serve as a target for plantaricin JK on sensitive cells.

Keywords: Antibacterial activity; bacteriocins; membrane proteins; mode of action.

Figure 1

The APC superfamily protein encoded by the gene that was mutated in the 10 plantaricin JK‐resistant strains. (A) The amino acid sequence of the protein. (B) The predicted membrane topology of the protein. The green curve shows predicted transmembrane regions, the red curve cytoplasmic regions, and the blue curve extracellular regions. Below these curves, the protein products expected from the gene mutations are shown schematically for the 10 mutants.