Figure 5.

Unbinding forces of the single- and the double-headed kinesins. (a) Schematic illustration showing the method of application of external load to one-headed or two-headed kinesin-coated bead by using optical tweezers. The relative size of the bead compared with kinesin is reduced to about one-tenth of the actual scale. In this illustration, the load is applied towards the plus-end of a microtubule. Unbinding-force distribution for (b) one-headed kinesin and (c) conventional two-headed kinesin at several nucleotide states towards the plus-end of the microtubule. (Adapted from Uemura et al. 2002.)