Hysteresis in Pressure-Driven DNA denaturation
L.A. Nicasio-Collazo [1], E. Hernández-Lemus [2+3], R. Castaneda-Priego [1]

[1] Departamento de Fisica, Universidad de Guanajuato, Leon, [2] Departamento de Genomica Computacional, Instituto Nacional de Medicina Genomica, Mexico, D.F., Mexico, [3] Centro de Ciencias de la Complejidad, Universidad Nacional Autonomca de Mexico, Mexico, D.F., Mexico

Abstract: A theory that accounts for the observation of hysteresis in pressure-driven DNA denaturation is proposed, combining an irreversible thermodynamic approach with an equation of state based on the Poisson-Boltzmann cell model. The theory predicts hysteresis curves for a DNA sequence in terms of the system parameters, i.e., salt concentration, density of DNA molecules and temperature. A great deal of attention has been drawn to thermal driven denaturation processes in the past. In recent times, the discovery of stress-induced denaturation, observed at the one-molecule level has revealed new insights into the complex phenomena involved in the thermo-mechanics of DNA function. Understanding the effect of local pressure variations in DNA stability is thus an appealing topic. Such processes as cellular stress, dehydration, and changes in the ionic strenght of the medium could account for such local pressure changes that will affect the molecular mechanics of DNA and hence its stability. Moreover, since this study incorporates the effect of pressure through a thermodynamic analysis, much of what is known from temperature-driven experiments will shed light on the pressure-induced melting issue.