TABLE 4

Inhibitory activity of a selection of DKA derivatives in the MB versus plasmid assay with PA-Nter, or an assay using untruncated PA

IC₅₀ (μM), 50% inhibitory concentration. For each compound the IC₅₀ value was calculated using nonlinear regression analysis. Values are the mean of at least two independent experiments.

Compound	PA-Nter, molecular beacon assay						Plasmid assay^{^c} Mn²⁺	Untruncated PA^d Mn²⁺
	MB-U₆A₂U₇-DFO^{^a}			MB-het2-DFO^{^b}
	Mn²⁺	Mg²⁺	No metal	Mn²⁺	Mg²⁺	No metal
1	1.5	3.1	2.5	3.9	7.1	3.5	0.5	0.5
5	3.9	6.3	9.1				0.5
10	4.2	177	100	2.4	>200	>200	0.8
12	154	>200	>200				2.7
30	26	41	41				3.4	1.1
31	3.2	44	54				22
34	3.6	59	180				0.6
39	21	>200	>200				0.6	1.1
40	5.2	>200	174				0.8
41	1.4	86	98				1.6
42	23	65	72				3.5

↵^a MB-U₆A₂U₇-DFO, 5′‐[DFO]‐GCAGG (dU)₆A₂(dU)₆ CCTGC‐[BHQ2]‐3′.
↵^b MB-het2-DFO, 5′-[DFO]‐CGCACG TTATGCTAAGCAAGTAACC GTGCG‐[BHQ2]‐3′.
↵^c Same data as in Tables 1 and 2.
↵^d See Noble et al. (2012) for a description of the fluorescence-based enzymatic assay with untruncated PA expressed in insect cells.