Figure 3. Curli display stop-and-go growth kinetics.

(a) High-speed time lapse imaging of a single growing fiber terminus (still images are frames of Supporting Video 3); (b) kymograph constructed from the fiber terminus followed in the upper panel reveals the stop-and-go dynamics of fiber growth; (c) representative traces of the fiber terminus location as a function of time at low and high CsgA concentration; (d) box-plot of the observed fiber elongation rate (r_obs, i.e. the global fiber elongation rate composed of periods of stagnation and burst elongation) averaged over 10 different fibers per concentration (box range = sample standard deviation; □ = sample mean; dashes show the minima and maxima of the dataset); (e) kymograph constructed from high speed AFM imaging at 45 nM CsgA shows the typical minimal detectable size of the fiber end displacements of 12±4 nm (mean elongation rate is 0.1±0.05 nm/s (see panel d); time-resolution: 10s). Figures (a), (b) and (e) correspond to the AFM error channel.