Fig. 4.

ATP-induced isomerization of HFG380B2 bound to MT. (A) Representative time courses of the ATP-induced isomerization of 0.05 μM HFG380B2 in the presence of 1 μM MT after mixing with 10, 50, and 250 μM ATP (jagged black curves). The smooth red curves are fits to the equations for the two-step reaction (see text) with k_iso values of 270 s⁻¹ (10 μM ATP), 140 s⁻¹ (50 μM ATP), and 200 s⁻¹ (250 μM ATP). (B) The k_iso values are plotted against ATP concentration. Error bars represent standard deviations.