TABLE 1.

Summary of kinetic parameters, metal binding stoichiometry, and affinity of mycobacterial P_1B4-ATPases

	M. smegmatis CtpJ		M. tuberculosis CtpD		M. tuberculosis CtpJ
	Fe2+	Co2+	Fe2+	Co2+	Fe2+	Co2+
ATPase activitya
Vmax (μmol/mg/h)	2.73 ± 0.12	0.62 ± 0.03b	4.25 ± 0.19	0.35 ± 0.03b	2.16 ± 0.07	1.38 ± 0.12b
K1/2 (μm)	350 ± 45	4.1 ± 0.9b	443 ± 54	4.8 ± 1.4b	143 ± 18	6.3 ± 2.2b
Metal stoichiometryc	1.0 ± 0.1	0.9 ± 0.1b	1.1 ± 0.1	1.1 ± 0.1b	1.1 ± 0.1	1.1 ± 0.3b
Metal binding affinityd
KD (μm)	2.24 ± 0.43	2.59 ± 0.32b	0.12 ± 0.04	0.33 ± 0.04	2.41 ± 0.27	1.60 ± 0.16
N	1.44 ± 0.17	1.39 ± 0.22b	1.32 ± 0.11	1.26 ± 0.04	1.35 ± 0.06	1.38 ± 0.05

^a Values are the best fit parameters of activity versus Fe²⁺ curves. Errors are asymptotic errors provided by the fitting software (Fig. 3D).

^b Values were previously reported (15, 16).

^c Values are the mean ± S.E. (n = 3).

^d Values obtained by competitive metal binding with mag-fura-2. Values are the mean ± S.D. (n = 3).