Fig. 1.
(A) Step-size measurements of tail- and head-labeled GST-Dyn331kD with a single QD-655 at 2-msec temporal resolution. The QD position (blue traces) was fit by a step-finding algorithm (solid red lines). (B) Multiple Gaussian fits to step-size histograms reveal two major peaks at 9.3 and 17.5 nm for the head and 4.8 and 8.7 nm for the tail. (C) Dwell-time histogram of head-stepping fitted to a convolution of two unequal rate constants and that of tail-stepping fitted to a model assuming uncoordinated stepping between two heads, each with two unequal rate constants.