FosB, a cysteine-dependent fosfomycin resistance protein under the control of σW, an extracytoplasmic-function σ factor in Bacillus subtilis

We demonstrate that the Bacillus subtilis fosB(yndN) gene encodes a fosfomycin resistance protein. Expression of fosB requires sigma (W), and both fosB and sigW mutants are fosfomycin sensitive. FosB is a metallothiol transferase related to the FosA class of Mn2+-dependent glutathione transferases but with a preference for Mg2+ and L-cysteine as cofactors.