FIG. 3.

Deletion analysis of the RtsA-inducible dsbA promoter region. The serovar Typhimurium strains were ΔrtsAB and contained pBAD30 or pRtsA and lacZ transcriptional fusions to the region of dsbA indicated below the graph. The locations of the regions (in precise base pairs) are shown in Table 1. The E. coli strains were ara⁺ derivatives of MC4100 with either pBAD30 or pRtsA and contained either a serovar Typhimurium dsbA-lac fusion integrated at the λatt site or an E. coli dsbA-lac fusion integrated at the λatt site. Overnight cultures were subcultured in LB medium containing ampicillin and 0.2% l-arabinose and were grown to an optical density at 600 nm (OD₆₀₀) of ∼0.6. β-Galactosidase activity values were determined as follows: (micromoles of o-nitrophenol formed per minute) × 10³/(OD₆₀₀ × milliliters of cell suspension). The values are means ± standard deviations (n = 4). The fold induction values for the fusions are indicated at the bottom. The strains used were plasmid-containing derivatives of JS342 through JS351, JS353, and JS354.