Figure 2.

Distributions of the Translocation Velocity and Loop Size for SWI/SNF

Distributions of the translocation velocity (A) and loop size (B) for SWI/SNF. In (A), the histograms for positive and negative velocity values are separately fitted with Gaussian functions (red), yielding the indicated means and standard deviations of 5 bp/s for the positive translocation and of 6 bp/s for the reverse translocation. The accumulative translocation length at the specified velocity is shown. In (B), the loop size for each loop formation event is defined as the corresponding DNA contour-length change from the start point of the first translocation phase to the endpoint of the last translocation phase. The loop size for reverse translocation is the DNA length that is removed from the loop after its maximum size is attained. Note that velocity and loop size values outside the range drawn (±30 bp/s for velocity and −200/+500 bp for loop size) are binned to the corresponding endpoints. The distributions were calculated (Experimental Procedures) from 241 DNA-looping events measured on 67 different DNA molecules.