Fig. 4.

Mechanistic model describing helicase grip in different energy states. a Schematic representation of the three observable helicase states (see text). Gray circle represents NA. Colored clips represent helicases clamping NA more or less tightly. b Binding and sliding times plot versus increasing binding energy differences represented with a logarithmic scale in y. For each helicase i, the sliding time τ_S, the unwinding time τ_U and the falling time τ_R are drawn in logarithmic scale against the binding energy difference ΔE_bi1 = E_bi − E_b1 measured in units of k_BT (E_b1 corresponds to UPF1^AKS→HPA binding energy). Each helicase has its three representative points located at the same abscissa. Full lines are exponentials predicted by Supplementary Equation 3 (Supplementary Note). Distance between the lines reflects the energy difference between these three states. Error bars indicate standard deviation