Table 1.

EC₅₀ values of wild-type and mutant CNF toxins^a

Toxin	EC50 (nM)b	EC50 ratioc
		CNF3	CNFy
CNFy	0.43 ± 0.06	—	1
CNF3y-223	0.21 ± 0.02	—	0.5
CNF3y-519	0.23 ± 0.02	—	0.5
CNF3y-428	0.052 ± 0.004	—	0.1
CNF3y-317	0.075 ± 0.006	—	0.2
CNF3y-349	0.28 ± 0.04	—	0.7
CNF3y-375	0.20 ± 0.01	—	0.5
CNF3y-412	0.056 ± 0.006	—	0.1
CNFy E374Q	0.25 ± 0.04	—	0.6
CNFy E412S	0.30 ± 0.05	—	0.7
CNFy E374Q/E412S	0.10 ± 0.09	—	0.2
CNF3	0.017 ± 0.003	1	—
CNF3 Q373E	0.045 ± 0.008	2.6	—
CNF3 S411E	0.032 ± 0.006	1.9	—
CNF3 Q373E/S411E	0.094 ± 0.019	5.5	—
CNF3 Q373K	0.13 ± 0.01	7.6	—
CNF3 E412A	0.066 ± 0.017	3.6	—
CNF3 E412K	0.095 ± 0.015	5.6	—

^aThe EC₅₀ values were calculated from dose–response assays determined from this study.

^bThe EC₅₀ values represented are mean ± SEM calculated using nls in R.

^cThe EC₅₀ ratio was determined by dividing the EC₅₀ of the chimeric proteins by that of the native CNF toxin with the same cargo domain A.