Molecular field theory of hysteresis in helix-coil transitions of polynucleotides

A molecular field theory, taking into account long-range electrostatic forces is used to study helix–coil transitions of polynucleotides. The theory predicts the existence of hysteresis when the electrostatic interaction parameter is large compared to the thermal energy. The theory is applied to the acid–base titration of poly(A)·2 poly(U).