Figure 4.

EM images of MinC–MinD–FtsZ copolymers at different assembly times. A and B, premixed MinD, FtsZ, ATP, and GTP, initiated by addition of MinC, showed bundle formation within 30 s (A) and very large bundles at 150 s (B). C–F, premixed MinC, MinD, and FtsZ induced by the addition of ATP showed only small filaments at 40 s, which is within the lag period (two examples are shown, C and D). Single FtsZ filaments are seen in high contrast in C and in lower contrast in D (this field was chosen to show rare small bundles). Bundles appeared at 2 min (E), and very large bundles were obvious at 3 min (F). The concentration of MinD was 10 μm, MinC was 5 μm, and FtsZ was 5 μm. Both ATP and GTP were 1 mm. Bars are 200 nm.