Western blot analysis of E. coli periplasmic fractions and broth cultures with antisera against DraD. Visualization of DraD expressed by E. coli strains with a disrupted (A) and complemented (B) gspD gene with a rabbit anti-DraD serum. All preparations were isolated from the same amount of bacteria (optical density at 600 nm, 0.5). A rabbit anti-DraD serum was used as the primary serum, and a peroxidase-coupled anti-rabbit serum was employed as the secondary serum. (A) Lane M, PageRuler Prestained Protein Ladder Plus (Fermentas) for 250, 130, 100, 70, 55, 35, 27, 15, and 10 kDa; lanes 1 and 2, periplasmic (P) and supernatant (S) fractions of E. coli BL21(λDE3)/gspD; lanes 3 and 4, periplasmic (P) and supernatant (S) fractions of E. coli BL21(λDE3)/gspD-pCC90; lanes 5 and 6, periplasmic (P) and supernatant (S) fractions of E. coli BL21(λDE3)/gspD-pCC90D54stop; lanes 7 and 8, periplasmic (P) and supernatant (S) fractions of E. coli BL21(λDE3)/gspD-pCC90DraDmut; lanes 9 and 10, periplasmic (P) and supernatant (S) fractions of E. coli BL21(λDE3)/gspD-pCC90DraCmut. (B) Lane M, PageRuler Prestained Protein Ladder (Fermentas) for 250, 130, 100, 70, 55, 35, 27, 15, and 10 kDa; lanes 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 contain periplasmic (P) and supernatant (S) fractions of E. coli BL21(λDE3)/gspD (lanes 1 and 2) complemented with pET30-gspD and harboring pCC90 (lanes 3 and 4), pCC90D54stop (lanes 5 and 6), pCC90DraDmut (lanes 7 and 8), or pCC90DraCmut (lanes 9 and 10) plasmids.