585748.fig.004a
(a)
585748.fig.004b
(b)
Figure 4: Determination of kinetic parameters for the interaction of EF-Tu with GDP in the absence of EF-Ts. (a) Initial velocities for P. aeruginosa EF-Tu in GDP exchange reactions were determined at various concentrations of GDP. The concentration of EF-Tu was held constant at 0.64 μM. The velocities were measured between 1 and 4 min to minimize the chance of measurement of exchange occurring during mixing but before the beginning of the incubation period. The concentrations of GDP were ■, 4 μM; ◯, 6 μM; ▴, 8 μM; , 10 μM; ●, 12 μM. (b) The data from the initial velocity experiments were used to develop a Lineweaver-Burk plot to determine kinetic parameters for the interaction of P. aeruginosa EF-Tu with GDP in the absence of EF-Ts.