Determining the DNA stability parameters for the breathing dynamics of heterogeneous DNA by stochastic optimization

We suggest that the thermodynamic stability parameters (nearest neighbor stacking and hydrogen bonding free energies) of double-stranded DNA molecules can be inferred reliably from time series of the size fluctuations (breathing) of local denaturation zones (bubbles). On the basis of the reconstructed bubble size distribution, this is achieved through stochastic optimization of the free energies in terms of Simulated Annealing. In particular, it is shown that even noisy time series allow the identification of the stability parameters at remarkable accuracy. This method will be useful to obtain the DNA stacking and hydrogen bonding free energies from single bubble breathing assays rather than equilibrium data.

💡 Research Summary

The paper introduces a novel method for extracting the thermodynamic stability parameters of double‑stranded DNA—specifically the nearest‑neighbor stacking and hydrogen‑bonding free energies—directly from the dynamics of local denaturation bubbles (breathing). Traditional approaches rely on equilibrium measurements such as UV melting curves, calorimetry, or single‑molecule unzipping experiments, which often yield inconsistent parameter sets. In contrast, the authors propose to use time‑resolved bubble size fluctuations as the sole source of information.

A statistical‑mechanical model of DNA breathing is first constructed. Each base pair contributes a hydrogen‑bonding Boltzmann factor u_hb(x)=exp