Fig. 6

Mean stepping time (‘baseline’, \(\kappa =1\) nm/s) of a walker-foothold complex (36 bps) in absence of tail and trench (solid, blue) estimated from our fitted distributions using Eq. (3) in the reaction-limited regime as a function of the distance between the tethering point and the target, a. Normalized stepping rates (with respect to the baseline) estimated from our fitted distributions using Szabo’s equation for a tailed foothold (12 bps tail, 36 bps complex, dash, red), a trench (36 bps complex, dots, red), and a combined tail-trench system (12 bps tail, 36 bps complex, dash-dot, red). The ssDNA toeholds employed by Li et al. ²⁰ that allow the walker to bind to the next foothold consist of 8 nts. These strands exhibit a contour length of \(\sim 5\) nm ⁴³, a Kuhn length of 1.6 nm ⁴⁴ and (by means of worm-like chain estimates ⁴⁵) an end-to-end distance of 3.4 nm. We then consider \(\epsilon =2\) (a), 3.5 (b), and 5 (c) nm for our analysis. In all calculations, \(D=50\) \(\upmu \hbox {m}^{2}\)/s was taken, leading to negligible contributions of the diffusion-limited term to \(\tau\).