Microtubule–Kinesin in Vitro Motility Assays.

Microtubule–kinesin gliding assays were performed using full-length kinesin-1 (kinesin) from Drosophila (49) and rhodamine-labeled tubulin (50) by following a procedure (51) that was upgraded for motility in nanochannels (52). The SiO₂ surface of the computational chip was passivated with 2-[Methoxy(poly-ethyleneoxy) propyl] trimethoxysilane] to prevent protein binding anywhere except on the gold bottom of the channels. Flow cells were perfused with (i) casein-containing solution (0.5 mg ml⁻¹, 5 min); (ii) kinesin solution (2 nM, 5 min); and (iii) motility solution containing 1 mM ATP and rhodamine-labeled, taxol-stabilized.