Table 2. Inhibitory Activities of 7a against DNA Gyrase and Topo IV from S aureus, E. coli, A. baumannii, and P. aeruginosa.

		IC50 [nM]a
enzyme		7a	ciprofloxacin	novobiocin
S. aureus	DNA gyraseb	1.22 ± 0.04	12 170 ± 1 245	0.65 ± 0.03
	topo IVb	8.0 ± 1.2	6 075 ± 1 648	13 265 ± 7
E. coli	DNA gyrasec	<10	120 ± 20	170 ± 20
	topo IVc	44 ± 11	5 400 ± 2 100	11 000 ± 2 000
A. baumannii	DNA gyraseb	2.42 ± 0.28	1 267 ± 344	2.17 ± 0.16
	topo IVb	119.7 ± 8.34	2 885 ± 332	9 465 ± 799
P. aeruginosa	DNA gyrasec	<10	ntd	nt
	topo IVb	27.5 ± 16.3	3 895 ± 63.6	8 365 ± 445

^aIC₅₀, concentration (mean ± SD of three independent experiments) that inhibits enzyme activity by 50%.

^bTested in gel-based supercoiling (for DNA gyrase) and decatenation (for topo IV) assays.

^cTested in supercoiling (for DNA gyrase) and relaxation (for topo IV) HTS assays.

^dnt, not tested.