FIGURE 5.
Fractional occupancy of the microtubule-binding site impacts the efficacy of allosteric monastrol-based inhibition of Klp61F-L5. In the presence of saturating ATP, the monastrol IC50 for Klp61F-L5 decreases with increasing microtubule concentration. In the presence of 1 μm taxol-stabilized microtubules, Klp61F-L5 motor domains are not inhibited by monastrol. However, the monastrol IC50 is 39 ± 10 and 5 ± 2 μm in the presence of 3 and 5 μm tubulin, respectively. The Wilcoxon signed rank test confirmed that all three datasets are significantly different from one another (α = 0.05).