Figure 8.
Effect of high MgCl2 concentration on polymerization of FtsZ or ΔCTL. A, fluorescence signal emitted over time (emission at 344 nm after excitation at 295 nm) for FtsZ or ΔCTL with 0.1 mm GMPCPP added at time = 0 min in HEK50 buffer (50 mm KCl). MgCl2 was added to the reaction to a concentration of 2.5 mm at time = 3 min and subsequently to a concentration of 10 mm at time = 11 min (mean of three replicates). Total concentration of protein in each reaction was 4 μm. L72W mutants when used were at 10% total protein concentration (3.6 μm FtsZ + 0.4 μm FtsZL72W, 3.6 μm ΔCTL + 0.4 μm ΔCTLL72W, 4 μm FtsZ alone, or 4 ΔCTL alone). B, signal specific to tryptophan fluorescence (calculated by subtracting mean of signal for FtsZ or ΔCTL alone from mean of corresponding signal for FtsZ + FtsZL72W or ΔCTL + ΔCTLL72W, respectively) for experiment in Fig. 6A. C, right angle light scatter (emission at 350 nm after excitation at 350 nm) over time for 4 μm FtsZ or ΔCTL with 0.2 mm GMPCPP added at time = 0 min in HEK50 buffer (50 mm KCl). MgCl2 was added to reaction to a concentration of 2.5 mm at time = 4 min and subsequently to a concentration of 10 mm at time = 12 min (mean of at least three replicates).