FIGURE 2.
Effect of temperature on pause duration and the speed of the 120° step. A, observation of the pause duration (catalytic dwell) and the speed of the 120° step. Examples are shown of aligned 120° rotation steps for 17 and 24 °C experiments (data collection rate, 4,000 frames/s). B, effect of temperature on pause duration and time length of the 120° rotation step. Rotations of gold beads were followed for 2 s at the indicated temperatures. The average time required for the 120° revolution (as shown in A) includes the short pause and 120° step. Time for the pause duration was determined by subtracting the time for 120° rotation step from the time for the 120° revolution. These values were determined over 900 120° revolutions, and the average pause duration (black bars) and time length of 120° rotation steps (open bars) are shown. Essentially, the same values were obtained using 8,000 frames/s. The error bars indicate standard errors. C, Arrhenius plots of speed of the 120° step (in s−1) determined from the time lengths of the steps (open circles) and the reciprocal of the pause duration (closed circles).