FIG. 5.
The tibDB promoter is activated by CRP. β-Galactosidase activities of tibDBp::lacZ reporters integrated into the chromosomal attBHK022 site of wild-type strain BW25113 or crp::kan strain JW5702 are shown. Assays were conducted in triplicate on two successive days (n = 6), and error bars show the standard deviations of the means. P values were calculated using the Student t test. (A) Reporter strains GPM1710 (WT) and GPM1713 (crp::kan) carrying attBHK022::pTibDBLac1 (tibDBo). For complementation assays, GPM1713 was transformed with pDCRP (crp+) or pDU9 (vector). (B) tibDBp activity in wild-type (WT) and crp::kan reporter strains carrying the natural CRP binding site tibDBo or the mutagenized binding sites tibDBo1 and tibDBo2.