DNA overstretching transition induced by melting in a dynamical mesoscopic model.

We present a phenomenological dynamical model describing the force induced melting as responsible for the DNA overstretching transition. The denaturation mechanism is developed under the framework of the mesoscopic one-dimensional Peyrard-Bishop-Dauxois (PBD) picture which models the melting features of a polymer chain by means of a Morse potential and the stacking interaction. We find a good agreement with both the experimental overstretching curve and the asymmetric hysteretic properties with different simulation times. The comparison of the standard PBD model with a modification of the Morse potential which takes into account the interaction with the solvent has been also successfully investigated.