FIG. 3.

Effects of α-CTD alanine substitution mutants on rhaSR activation. Expression was measured from Φ(rhaS-lacZ)Δ216 (SME1074) cells carrying wild-type (w.t.) rpoA on a plasmid or a plasmid encoding α with a single alanine substitution at each position in α-CTD. Cells were grown in MOPS growth media containing glycerol, l-rhamnose, and 125 μg of ampicillin/ml. Values are the average of at least three independent assays and are shown as a percentage of the average expression from cells carrying wild-type rpoA on a plasmid. Analysis of variance was used to determine which alanine substitution mutants had significantly lower levels of expression compared to the wild type, which are indicated by an asterisk above the bar. β-Gal Act., β-galactosidase activity.