TABLE 2.
Cation-dependent ATPase activities of purified KdpFABC-His10 complexesa
| Complex | Fold change in ATPase activity (K0.5 [mM]) withb:
|
|||||
|---|---|---|---|---|---|---|
| K+ | Rb+ | NH4+ | Na+ | Li+ | Cs+ | |
| KdpFABC-His10 (wild type) | 2.3 (0.07) | 2.2 (1) | 1.0 (—) | 1.3 (5) | 18.6 (2) | 1.1 (10) |
| G345A mutant | 1.2 (10) | 2.9 (1) | 1.5 (6) | 1.5 (11) | 1.4 (80) | 1.4 (50) |
| G345D mutant | 3.8 (0.5) | 5.9 (3) | 1.0 (—) | 1.0 (—) | 2.9 (10) | 1.0 (—) |
| G345S mutant | 2.0 (1) | 1.8 (3) | 1.5 (15) | 1.0 (—) | 3.7 (8) | 1.5 (30) |
| G470S mutant | 4.0 (5) | 18.0 (2) | 1.3 (9) | 1.3 (0.9) | 3.6 (1) | 4.7 (0.5) |
| S471G mutant | 2.9 (0.2) | 1.9 (2.5) | 1.9 (3) | 1.1 (10) | 4.7 (1) | 2.8 (30) |
a
Data represent average values obtained in at least three independent experiments.
b
Values for stimulating cations are in boldface, and values for inhibiting cations are in lightface; change was measured in the presence of saturating concentrations of the different cations. Values of 1 represent no stimulation or inhibition. K0.5 values for half-maximal stimulation or inhibition are given in parentheses. —, K0.5 = 0.