FIG. 2.

Effects of alanine substitutions in α on LuxRΔN-dependent (A) and LuxR-dependent (B) cellular luciferase levels in recombinant E. coli. The value for each variant form of α represents the average of two independent experiments with individual luciferase assays performed in quadruplicate. The error bars represent the range of each experiment from the mean. Luciferase activities from strains containing either of the two wild-type (WT) controls, pHTf1α or pREIIα, were set to 100% for each experiment. The solid bars highlight variants producing <50% wild-type levels of luciferase activity, the hatched bar highlights a variant producing >200% wild-type levels of luciferase activity, the open bars are used at positions where the variants exhibited luciferase levels within twofold of the wild-type, and the shaded bars are used to represent positions were alanine is already present in wild-type α.