Figure 6.

Single-turnover kinetics of DNA unwinding with different PcrA concentrations. A 20 nM 20-nt-tailed 16-bp duplex substrate was first pre-incubated with PcrA at the indicated concentrations in the reaction buffer at 25°C and the unwinding reaction was initiated by adding 1 mM ATP and excessive protein trap (dT₅₆, 2 μM). (A) Kinetic time-courses. The solid lines shown were the best fits of the data to Equation (3) with n=3. (B) Amplitude of unwinding as a function of [PcrA]. The solid line represented a sigmoidal fit of the data. (C) The observed rate constant for each step of DNA unwinding.