FIG 3.
EssE is required to stabilize EssD. (A) S. aureus cultures of strain USA300 or its isogenic ΔessE, ΔessE/pessE, and essD::erm variants were grown to an A600 of 1.0, and lysostaphin was added to the whole culture. Proteins were TCA precipitated and separated by SDS-PAGE as described in the legend to Fig. 2A. Immunoblot analyses were performed using rabbit polyclonal antibodies specific for the N- and C-terminal domains of EssD (α-EssDN and α-EssDC) and membrane protein SrtA. Arrows point to various polypeptides that are specifically recognized by EssD antibodies. (B) Extracts of the USA300 strain or its isogenic essD::erm variant with or without complementing plasmid (pessD) were prepared as described for panel A and examined by immunoblotting for the presence of EssE and ribosomal protein L6.