FIGURE 4.

Angular positions of SP and ATP binding. A, X-Y trajectories of a single V₁ molecule at 4 μm ATP (top panel) and at 4 mm ATP (bottom panel). After observing a rotation at 4 μm ATP in which V₁ demonstrated ATP-waiting pauses, the ATP concentration was increased by buffer exchange to 4 mm, at which V₁ demonstrated the SPs. Therefore, three positions in each trajectory represent the ATP-waiting angles and the SP angles, respectively. B, angle histograms of the single molecule of V₁ is shown in A at 4 μm ATP (top panel) and at 4 mm (bottom panel). Dotted lines show the mean positions of ATP-waiting angles and the SP angles. C, angular deviation between ATP binding and SP dwell determined from 48 observations. Mean is 0.6 ± 12°.