Figure 11.

Lrp effects on orthologous promoter regions in three backgrounds. The orthologous Plrp or PgltB regions were amplified from E. coli, P. mirabilis, and V. cholerae and inserted upstream of a promoterless lacZ gene. These plasmids were then used to transform lrp/lrp⁺ strain pairs of all three species, and lacZ was measured vs. culture density to obtain the slopes. Black bars indicate expression in the E. coli WT (upper panels) or lrp (lower panels) background, gray bars indicate expression in the P. mirabilis strain pair, and white bars represent expression in the V. cholerae strain pair. For each least squares fit, yielding the plotted slope value, the correlation coefficient was ≥0.97. The standard error for each slope was calculated from the residuals using the "summary(lm(y~x))" function from the R statistical package. All strains were grown in MOPS glucose medium supplemented with nicotinate, pantothenate, thiamine, methionine and cysteine (see Methods).