TABLE 3.

Effect of novobiocin on expression of cpxA, invG, and prgH

Straina	Locus	Novobiocin concn (μg/ml)	Mean PhoA activity (Miller units)b ± SEM
A1	Z::TnphoA	0	124 ± 10
		2	160 ± 5
		5	38 ± 6
		10	109 ± 6
K14	invG	0	376 ± 47
		2	42 ± 0.2
		5	39 ± 1
		10	46 ± 3
H5	prgH	0	928 ± 367
		2	53 ± 4
		5	27 ± 1
		10	29 ± 1
I25	cpxA	0	127 ± 2
		2	177 ± 6
		5	169 ± 7
		10	119 ± 4

^aStrains were grown to mid-logarithmic phase (OD₆₀₀ of ≈0.6) in LB–0.3 M NaCl with or without various concentrations of novobiocin. Cell extracts were prepared by sonication, and the amount (milligrams) of protein was determined by the Bio-Rad assay. 

^bAlkaline phosphatase activity was measured as described in Materials and Methods. The data represent means from two independent experiments.