Figure 5. Ability to phosphorylate S59 increases stressosome sensitivity.

(A) Peak β-galactosidase accumulation from a ctc-lacZ fusion after addition of different concentrations of ethanol. Strains encoded a minimal stressosome containing RsbRA as sole co-antagonist and either wild type RsbS (PB1078; open bars) or RsbS bearing the S59A substitution (PB1161; shaded bars). Error bars represent range in two independent assays. (B) Closed symbols indicate fraction of parental activity manifested by S59A mutant at each ethanol concentration (data from A); open symbol indicates fraction at 0.3 M NaCl (see text).