Fig. 2: Step-type probabilities and F/B step ratios under load in ATP versus ATPγS.
From: ATPγS substantially defeats the biasing mechanism for kinesin steps
a, b Probability of forward steps (blue), <12 nm backsteps (orange), >12 nm backsteps (reddish-brown), and detachments (yellow) versus load for optically trapped kinesin-1 beads in (a) 1 mM ATP, (b) 1 mM ATPγS, (i) 1 μM ATP, and (j) 1 μM ATPγS. c, d, g, h, k, l F/B ratio (#forward steps / #backsteps) versus load. c 1 mM ATP (fitted: 2-7 pN), F/B ratio = 714 e-0.78 * load, d 1 mM ATPγS, k 1 μM ATP (fitted: 3-6 pN), F/B ratio = 197 e-0.76 * load, and l 1 μM ATPγS (fitted: 3-6 pN), F/B ratio = 100 e-0.74 * load. e–h equivalent to a–d except sampling of the area shaded grey was improved by stepping the stage at a trigger load to apply superstall force (Methods). g 1 mM ATP (fitted: 2–7 pN), F/B ratio = 977 e-0.88 * load. h 1 mM ATPγS. n = 8356 (c), n = 2491 (d), n = 9144 (g), n = 3166 (h), n = 750 (k), n = 1123 (l). Error bars show ±SEM.
