Staphylococcus aureus sortase mutants defective in the display of surface proteins and in the pathogenesis of animal infections

Many Gram-positive bacteria covalently tether their surface adhesins to the cell wall peptidoglycan. We find that surface proteins of Staphylococcus a ureus are linked to the cell wall by sortase, an enzyme that cleaves polype ptides at a conserved LPXTG motif. S. aureus mutants lacking sortase fail t o process and display surface proteins and are defective in the establishme nt of infections. Thus, the cell wall envelope of Cram-positive bacteria re presents a surface organelle responsible for interactions with the host env ironment during the pathogenesis of bacterial infections.