Figure 7.

Predictions for sequence dependence of T7 detachment and backstepping rates while unwinding dsDNA. (a) The backstepping rate while unwinding $\left(k_{-}^{\text{'}}\right)$ hardly changes as a function of the sequence stability as a result of the helicase being only weakly active. (b) Similarly, the detachment rate while unwinding $\left(k_d^{\text{'}}\right)$ changes by only a factor of 1.5 with change in ΔG. The insets in both figures show the hypothetical situation of a highly active T7, with U₀ = 2.0 k_BT. Both the backstepping and detachment rate show much more sensitivity to ΔG under highly active circumstances. To see this figure in color, go online.