Figure 3

Plasmid containing phosphorylation-deficient arcA complements the ΔarcA mutant E. coli in resistance to H ₂ O ₂ . The wild type E. coli (diamond), ΔarcA mutant E. coli (square), ΔarcA mutant E. coli transformed with plasmid vector pRB3-273C (cross), ΔarcA mutant E. coli transformed with plasmid pRB3-arcA (triangle) and ΔarcA mutant E. coli transformed with plasmid pRB3-arcD2A which contains a phosphorylation-deficient arcA allele (circle) were incubated with LB medium containing 1.5 mM H₂O₂ at 37°C. The survival of bacteria was determined by plating and plotted against the indicated incubation time period. At least three experiments were performed, and results from a representative experiment performed in triplicates are shown. Error bars indicate standard deviation and sometimes fall within the data label.