Figure 6. Visualization of Individual ClpXP Translocation Steps.

(A)–(G) For the y-axis of each panel, the black numbers represent amino acids, assuming a WLC model with a persistence length of 0.61 nm (see Fig. 2B legend), and the red numbers represent changes in bead-bead distance. In panels A–C, the black vertical bars represent the smallest steps resolved. Experiments were performed using 2 mM ATP (A–E), 75 μM ATP (F), or 1 mM ATP plus 1 mM ATP S (G). Asterisks mark events that appear to be minor slipping of the substrate relative to ClpXP, which was more common during translocation under higher loads, at low ATP, or in ATP/ATP S mixtures.

(H) Power spectra (Svoboda et al., 1993) of pairwise-distance distribution functions of single translocation curves show main peaks near ~0.08 and ~0.16 aa⁻¹, corresponding to step sizes of ~6.25 (range 5.7–7.1) and ~12.5 (range 10–13) amino acids.