Figure 2.

Displacement and force transients of single or kinesin molecules initiated by flash photolysis of caged ATP at zero time. The initial concentrations of caged ATP were 500 (a), 100 (b), and 20 μM (c), leading to released ATP concentrations of 450, 90, and 18 μM, respectively. The displacements caused by kinesin were determined from the bead displacements by correcting for the effect of kinesin-to-bead stiffness. The arrows in the diagram indicate the moments when the displacements rose to 4 nm above the base lines. (d) Fifty-five traces, in which kinesin did not detach from microtubule for at least 350 ms after UV flashes, were averaged. No median filter was used.