Figure 4.

Force versus extension curves at 50 nm/s for the four different hairpins. The darker curves correspond to the stretching of the construct, whereas the lighter ones represent the release process. For both the DNA and RNA hairpins, the hysteresis between unfolding and folding increases with loop length. For the same hairpin sequence, the hysteresis is larger for the RNA construct than for the DNA one. The inset provides a closer look to the force flips observed with DNA10. In this inset, the unfolding and folding curves are shifted vertically for clarity.