FIGURE 5.

Effects of GDP of BtubA/B assembly. A, polymerization of 5 μm BtubA/B with 1 mm GDP/GTP mixtures in Tris-KCl buffer at 25 °C, quantified by pelleting; the line is drawn solely to show the trend of the data. B, polymerization-depolymerization time course of 5 μm BtubA/B with GTP and GDP additions. Polymerization of sample 1 (solid line) was initiated by 0.1 mm GTP, and 1 mm GDP and 1 mm GTP were subsequently added as indicated by the arrows at the bottom. Assembly was equally initiated in sample 2 (dashed line), but then 1 mm GTP and 1 mm GDP were added as indicated by the arrows at the top.