FIG. 3.

Cell wall anchor structure of staphylococcal surface proteins. The C-terminal threonine of surface proteins, generated by sortase A-mediated cleavage between the threonine and the glycine of the LPXTG motif, is amide linked to the pentaglycine cross bridge of S. aureus cell wall peptidoglycan. Treatment of the staphylococcal peptidoglycan with lysostaphin (glycyl-glycine endopeptidase), mutanolysin [N-acetylmuramidase that cleaves the β(1-4) O-glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine (GN)], amidase (N-acetylmuramoyl-l-Ala amidase), or Φ11 hydrolase (N-acetylmuramoyl-l-Ala amidase and d-Ala-Gly endopeptidase) releases surface protein with the predicted C-terminal cell wall anchor structures.