Antibacterial activity of cystobactamid A-ring analogs, given as minimal inhibitory concentrations (MICs) in μg mL⁻¹, and inhibitory activity against DNA gyrase in μM^e.

Compound				MIC [μg mL−1]					E. coli gyrase IC50 [μM]
				E. coli ΔtolCa	E. coli WTb	P. ae. ΔmexABa	P. ae. WTc	S. aureus d
	R
	o	m	p
Reference 4	H	H	NO 2	0.125	1	1	>64	1	0.11
14	H	H	NHAc	0.06	16	>64	>64	64	nd
15	H	H	H	0.5	>64	2	>64	>64	4.0
16	H	H	F	0.5	0.5	2	>64	2	nd
17	H	H	NH2	32	2	4	>64	>64	26.8
18	H	NO2	H	0.25	>64	0.5	>64	>64	2.2
19	H	NH2	H	2	32	4	>64	>64	nd
20	NO2	H	H	2	8	16	>64	>64	nd
21	H	H	NHCONH2	≤0.03	0.5	4	>64	64	8.7
22	H	H	CN	0.06	0.5	0.25	2	0.25	0.08
23	H	H	CF3	≤0.03	0.5	64	>64	16–32	nd
24	H	H		>64	0.5	>64	>64	>64	2.5
25	OH	i-PrO	NO2	>64	>64	>64	>64	>64	>50
26	OH	i-PrO	NH2	0.01	2	2–4	32	>64	50
27	H	H	SO2CH3	≤0.03	2	4	>64	>64	nd
28				8	16	>64	>64	>64	16
29				≤0.03	≤0.03	1	>64	1	1.4
30				≤0.03	≤0.03	1	>64	64	0.5
31				≤0.03	≤0.03	0.25	0.5	≤0.03	0.9
32				≤0.03	≤0.03	0.25	0.5	0.25	0.5
33				≤0.03	0.06	1	>64	4	nd
34				≤0.03	≤0.03	0.5	>64	64	0.7
35				>64	>64	>64	>64	>64	3.6
36				0.5	0.25	>64	>64	>64	0.3

^aStrain provided by collaborators, see ESI.

^bDSM-1116.

^cPA14.

^dATCC29213.

^end = not determined, P. ae. = P. aeruginosa.