FIG. 4.

(Left) Predicted length-dependence of the extension and torque jumps at F = 2 pN. Using the CS parameters extracted from the experiment, Eqs. (11)–(12) predict the L-dependence of Δx and Δτ. The circles show experimentally-measured values [with the torque jump here calculated from K* using Eq. (11)]. The lines show the predictions from data collected at two different overall DNA lengths L. (Right) Force-dependence of the extension and torque jumps, and predictions from two models. The Marko model does not include discontinuities at the transition. The elastic rod simulation and the simple end-loop model produce discontinuities of the correct order of magnitude, but neither fits the data well. Discrepancies can be attributed to misestimates of the four CS parameters in Fig. 3.