Table 2:
MgATP hydrolysis in the presence and absence of cluster. ATPase activity was measured as a function of MgATP in the presence and absence of [2Fe-2S](GS)4 cluster. Michaelis-Menten parameters were extracted, showing a decrease in KM in the presence of cluster. The increase in kcat/KM in the presence of cluster provides an indication of the effect of cluster on the efficiency of MgATP hydrolysis.
| 0 μM Cluster KM (mM) | 0 μM Cluster Vmax (μM / min) | 2.5 μM Cluster KM (mM) | 2.5 μM Cluster Vmax (μM / min) | fold decrease in KM | |
|---|---|---|---|---|---|
| Wild-Type | 2.5 ± 0.3 | 0.82 ± 0.03 | 0.027 ± 0.016 | 0.70 ± 0.03 | 93 |
| D398A | 1.0 ± 0.1 | 0.52 ± 0.02 | 1.5 ± 0.3 | 0.58 ± 0.04 | 0.67 |
| D398E | 1.2 ± 0.2 | 0.60 ±0.02 | 0.58 ± 0.18 | 0.33 ± 0.03 | 2.1 |
| D398K | 2.8 ± 0.3 | 0.90 ± 0.02 | 0.54 ± 0.13 | 0.46 ± 0.03 | 5.2 |
| D398N | 2.8 ± 0.5 | 0.63 ± 0.04 | 0.74 ± 0.18 | 0.43 ± 0.03 | 3.8 |
| D398R | 0.80 ± 0.10 | 0.62 ± 0.02 | 0.23 ± 0.04 | 0.62 ± 0.02 | 3.5 |