Producer self-protection against the lantibiotic epidermin by the ABC transporter EpiFEG of Staphylococcus epidermidis Tü3298

Abstract

Self-protection of the epidermin-producing strain Staphylococcus epidermidis Tü3298 against the pore-forming lantibiotic epidermin is mediated by an ABC transporter composed of the EpiF, EpiE, and EpiG proteins. We developed a sensitive assay based on HPLC analysis to investigate the capacity of the EpiFEG transporter to release epidermin and analogues from the cell surface to the external fluid. Our results indicate that the EpiFEG transporter works by expelling the lantibiotic from the cytoplasmic membrane into the surrounding medium. Analysis of transporter efficacy using nisin and gallidermin derivatives as substrates revealed a high substrate specificity. Furthermore, we showed that the activity of the gallidermin derivative L6G is enhanced by the presence of EpiE.