FIG. 2.

Sortase A-dependent surface display of staphylococcal proteins. Sortase is responsible for the anchoring of 20 different surface proteins to the cell wall of S. aureus strain Newman. One of these surface proteins, protein A, binds to the Fc terminus of mammalian immunoglobulins in a nonimmune fashion, causing decoration of the staphylococcal surface with antibody. Using Cy3-conjugated immunoglobulin and S. aureus strain Newman, protein A display on the bacterial surface was revealed with phase-contrast microscopy and fluorescence microscopy. Protein A display on the staphylococcal surface is abrogated in the srtA mutant strain (SKM3).