Site-Specific Serine Incorporation by Lif and Epr into Positions 3 and 5 of the Staphylococcal Peptidoglycan Interpeptide Bridge

The FemAB-like factors Lif and Epr confer resistance to glycylglycine endopeptidases lysostaphin and Ale-1, respectively, by incorporating serine residues into the staphylococcal peptidoglycan interpeptide bridges specifically at positions 3 and 5. This required the presence of FemA and/or FemB, in contrast to earlier postulations.