Figure 5. GpsB stimulates GTPase activity of FtsZ in vitro.

(A) Coomassie-stained gel of purified FtsZ, GpsB, and GpsB^L35S. (B) Size exclusion chromatograms of purified GpsB (top) or GpsB^L35S (bottom). Predicted multimerization states of the purified protein, based on migration of MW standards, is indicated above peaks (12X, dodecamer; 6X, hexamer). Shown is a representative example of at least 3 independent purifications. (C) Initial velocities of GTP hydrolysis by FtsZ as a function of time at various FtsZ concentrations. (D) GTP hydrolysis turnover rate of FtsZ as a function of FtsZ concentration. (E) GTP hydrolysis of increasing concentrations of GpsB alone (▲) or 30 μM FtsZ in the presence of increasing GpsB concentrations (●). Error bars represent SEM (n = 3). (F) Median GTP hydrolysis rates of 30 μM FtsZ and 10 µM FtsZ in the absence and presence of 10 μM GpsB or GpsB^L35S. The ends of the boxes represent the first and third quartile of measurements; bars represent the entire range of measurements; line indicates median value; ‘+' indicates mean value (n = 3).