Dual Role of GdmH in Producer Immunity and Secretion of the Staphylococcal Lantibiotics Gallidermin and Epidermin

The biosynthetic gene clusters of the staphylococcal lantibiotics epidermin and gallidermin are distinguished by the presence of the unique genes epiH and gdmH, respectively. They encode accessory factors for the ATP-binding cassette transporters that mediate secretion of the antimicrobial peptides. Here, we show that gdmH also contributes to immunity to gallidermin but not to nisin. gdmH alone affected susceptibility to gallidermin only moderately, but it led to a multiplication of the immunity level mediated by the FEG immunity genes when cloned together with the gdmT gene, suggesting a synergistic activity of the H and FEG systems. gdmH-related genes were identified in the genomes of several bacteria, indicating an involvement in further cellular functions.