Protein patterns of the putative sortase knockout strains. Samples were collected 8 h after induction. The cells were sonicated, followed by intensive washing and lysozyme treatment. Samples for SDS-PAGE and Coomassie blue staining were prepared as described in Materials and methods. The following strains have been analyzed: 1, NDH31/pNDH33 (ΔyhcS ΔywpE); 2, NDH31/pNDH33-yhcS (ΔywpE) (+P); 3, NDH31/pNDH33-ywpE; 4, NDH31/pNDH33-ywpE-yhcS; 5, NDH32 (ΔyhcS ΔywpE) derived from WB800 and 6, WB800N/pNDH33-ywpE-yhcS carrying yhcS and ywpE both on the chromosome and on the plasmid (+CP) were investigated. Strain NDH31 was derived from B. subtilis 1012, and NDH32 and WB800N were derived from B. subtilis WB800. The size of molecular weight standards is indicated on the left margin.