FosB, a Cysteine-Dependent Fosfomycin Resistance Protein under the Control of ς(W), 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 ς(W), and both fosB and sigW mutants are fosfomycin sensitive. FosB is a metallothiol transferase related to the FosA class of Mn(2+)-dependent glutathione transferases but with a preference for Mg(2+) and l-cysteine as cofactors.