Figure 4.

Analysis of motor slipping. (A) Mean frequency of slips (number detected per packaged kilobasepair) versus prohead filling measured with a 5 pN force clamp (n = 320 packaging events). (B) Mean frequency of slips versus applied force measured at low filling (<20%) in both force-clamp mode (where force is held constant at different preset values; circles, n = 190) and fixed-trap position mode (where force is allowed to build as packaging proceeds; squares, n = 130). The solid line is a linear fit to the data points. (C) Force resisting packaging versus prohead filling inferred from plots A and B. All error bars indicate mean ± SE.