Extended Data Fig. 9: RecBCD initiation kinetics at different pH values.

a, Single-molecule trajectories showing RecBCD initiation on blunt-end substrates at 50 μM ATP, solution pH 6, 10% glycerol, recorded at 500 Hz. Arbitrary vertical offsets are applied to different trajectories for display purposes. The region in the dashed box is magnified below, in which the wound and unwound angle states are marked in magenta and green, respectively. b, Single-molecule substrates showing RecBCD initiation on substrates with 6-nt 3′ or 10-nt 5′ overhangs, under the same conditions. The region demarcated by the dashed box is magnified in the inset. Data in a, b are representative of at least 3 independent biological replicates. c, d, Mean duration of initiation phase (total time from substrate binding until processive unwinding) for the blunt-end substrate and substrates with 3′ or 5′ overhangs at solution pH 6 (c) and solution pH 7 (d), 50 μM ATP, 10% glycerol. The green and magenta portions indicate the cumulative dwell times in the green and magenta states, respectively. Error bars are s.e.m. (n = 40, 27 and 44 (from left to right) trajectories in c; n = 149, 154 and 108 (from left to right) trajectories in d, from at least 3 independent biological replicates for each condition). Individual data points of the durations of initiation phase are overlaid as dot plots.