FIG 4.

Single mutations disrupt the antitoxin activity of VapB4 Δ54. (A) Spotting assay for E. coli strain LMG194 carrying the indicated plasmids carried out as described in the legend to Fig. 1B. (B) Single amino acid changes in the C-terminal 31-amino-acid domain of VapC4 and comparison with the same portion of VapB5. Each amino acid residue listed above VapB4 protein sequence represents a single mutation isolated from the screen. (C) Western blot analysis was carried out as described in the legend to Fig. 2C. The asterisk marks the position of an anti-GFP-positive band. (D) Spotting assay for E. coli strain LMG194 carrying the indicated plasmids carried out as described in the legend to Fig. 1B. (E) Western blot analysis was carried out as described in the legend to Fig. 2C.