FIGURE 3.

Effect of temperature on rotation, pause duration and speed of the 120° step of the γM23K mutant F₁. A, examples of 2-s time courses of randomly selected gold beads attached to the γM23K γ subunit at 17, 24, and 31 °C. B, Arrhenius plots of γM23K mutant F₁ rotation rates. Time courses of gold beads at different temperature were recorded for 2 s, and rotation rates were determined from the reciprocal of the geometric mean of the single revolution times (closed squares) or the arithmetic average of rotation rates (open circles). The γM23K F₁ bulk phase steady state ATPase activities are also shown (open triangles). The linear regression line of the wild-type rotation rate data from Fig. 1C is indicated by the dashed line. C, effect of temperature on the pause duration (black bars) and the time length of the 120° rotation step (open bars) of γM23K F₁. Pause duration and time length of the 120° rotation step were obtained as described for Fig. 2B. The rates were determined as in Fig. 2C. The error bars indicate standard errors. D, Arrhenius plots of the speed (in s⁻¹) of the γM23K F₁ determined from the time lengths of the 120° rotation steps (open circles) and the reciprocal of the pause duration (closed circles).