Figure 5.

Proposed reaction diagram illustrating the complete process of probe strand annealing (binding) and melting (unbinding) with complementary tethered DNA. Two free energy contours vs. DNA tether extension are drawn for both the probe strand unbound (blue) and bound (red) states. The initial annealing (binding) and final melting (unbinding) transitions are indicated by the labeled vertical wavy lines. The location of the annealing transition at the extension of the melting transition is assumed given the reversibility of the reaction, although the precise location is not directly measured. Relaxations and excitations of the DNA tether along the reaction contours are indicated by black arrows. The change in DNA tether extension upon annealing is labeled Δx_h. The distance to the melting transition state is labeled Δx₀.