Single molecule motility assays of myosins 10 and 5a along single actin filaments.

<p>(A) Still images from a movie showing movement of single molecules of m10-HMM-zip along a single actin filament. A series of images on the left panel shows the actin filament (red) and the fluorescently-labeled m10-HMM-zip in green at the indicated times. The images on the right are kymographs of the data depicted on the left. Red arrow heads show the moving m10-HMM-zip molecules and the yellow arrow heads show the molecules which attached and detached from actin without significant movement. (B) Velocity of single m5-HMM (open circle) and m10-HMM-Zip (closed circle) molecules at various ATP concentrations. Maximum velocities of m5-HMM and m10-HMM-Zip are 421 ± 38 nm/sec and 218 ± 29 nm/sec, respectively (mean ± S.D.). The data were fit to the Michael-Menten equation. (C) The run length distribution of m5-HMM (open circle) and m10-HMM-Zip (closed circle) at 1 mM ATP. Run length data were fit with single exponential equation (solid line). The mean run lengths of m5-HMM and m10-HMM-Zip were 1221 ± 255 nm and 755 ± 85 nm, respectively (mean ± S.D.). Data points from runs < 250 nm were omitted from the fits. The inset is the run-length of m5-HMM (closed bar) and m10-HMM-Zip (open bar) against ATP concentrations. Error bar is standard deviation (S.D.).