Figure 1.

DNA concentration dependence of UL9 ATPase activity. Kinetics of hydrolysis of a saturating concentration of ATP (3 mM) by 50 nM UL9 was determined in the presence of increasing concentrations of 38mer ss DNA (A) or partially duplex 23/38mer DNA (B). Observed rate constants (k_obs) were calculated as the maximum rate observed divided by the concentration of UL9 and were plotted as a function of ss or partially duplex DNA concentration (C and D, respectively). The data in C and D were fit to the Michaelis–Menten function (Equation 2) to predict the apparent kinetic constants reported in Table 1.