ABSTRACTThefmtAgene is a member of theStaphylococcus aureuscore cell wall stimulon. The FmtA protein interacts with β-lactams through formation of covalent species. Here, we show that FmtA has weakd-Ala-d-Ala-carboxypeptidase activity and is capable of covalently incorporating C14-Gly into cell walls. The fluorescence microscopy study showed that the protein is localized to the cell division septum. Furthermore, we show that wall teichoic acids interact specifically with FmtA and mediate recruitment of FmtA to theS. aureuscell wall. Subjection ofS. aureusto FmtA concentrations of 0.1 μM or less induces autolysis and biofilm production. This effect requires the presence of wall teichoic acids. At FmtA concentrations greater than 0.2 μM, autolysis and biofilm formation inS. aureusare repressed and growth is enhanced. Our findings indicate dual roles of FmtA inS. aureusgrowth, whereby at low concentrations, FmtA may modulate the activity of the major autolysin (AtlA) ofS. aureusand, at high concentrations, may participate in synthesis of cell wall peptidoglycan. These two roles of FmtA may reflect dual functions of FmtA in the absence and presence of cell wall stress, respectively.
Colony Spreading in Staphylococcus aureus
