Table 1.
RadA protein possesses DNA-dependent ATPase activity
| Addition or omission
|
Percent conversion of ATP or ADP
|
kcat (/min)
|
|---|---|---|
| −DNA | 2.0 | 0.01 ± 0.02 |
| +poly(dT)(37°C) | 2.7 | 0.02 ± 0.02 |
| +poly(dT)(65°C) | 14 | 0.12 ± 0.04 |
| +poly(dT)(75°C) | 17.5 | 0.14 ± 0.04 |
| +poly(dT)(85°C) | 20 | 0.17 ± 0.03 |
| +poly(dT) −Mg2+ | 0 | 0 |
| +M13 ssDNA | 8.7 | 0.06 ± 0.01 |
| +M13 ssDNA −Mg2+ | 0 | 0 |
| +M13 dsDNA | 4.3 | 0.03 ± 0.01 |
| +poly(dT) +dATP −ATP | 23 | 0.17 ± 0.03 |
The assays were conducted at 65°C, unless otherwise indicated, for 90 min. kcat values were determined from three different sets of data and calculated from the observed rate of ATP hydrolysis (μm ATP hydrolyzed/min) divided by the total concentration of RadA protein, as the concentration of ssDNA was in excess of the protein concentration.