Figure 4.

Movement of larger beads asymmetrically coated with ActA-His. (a) 2-μm-diameter carboxylated polystyrene beads shadowed from the left with silicon monoxide. Shadows can be seen on the protected side of the beads in this phase-contrast image. (Bar = 5 μm.) (b) Shadowed beads shown in a were incubated in situ with rhodamine-conjugated BSA and were washed and imaged using epifluorescence. Labeled protein adsorbed preferentially to the uncoated polystyrene surface. (c) Comet tail formation by a 1-μm-diameter shadowed carboxylated polystyrene bead, coated asymmetrically with ActA-His at 12.5% of available sites. (Upper) Phase-contrast. (Lower) Rhodamine-actin fluorescence. This bead is moving at a rate of 0.088 μm/sec. (d) 2-μm-diameter bead treated as in c moving at a rate of 0.019 μm/sec.