FIGURE 5.

For two filaments propelling a rigid object under load, an estimate of the protrusion speed can be obtained in the limit of D → ∞. The steady-state probability distribution can be separated into several regions, each with a protrusion velocity. The total average velocity is a statistical sum of these contributions. The protrusion velocity for two filaments as a function of the stagger spacing, x, is shown on the right. The actin concentration in this case is 100 μM. A load force of 13 pN is applied in the −z direction.