[B-form as the absolute energy minimum for DNA. Entropy nature of the B--A transition]

The B-form is characterizing by lower potential energy than A-form, especially if electrostatic term is added. For realistic values of epsilon (4; 1) spontaneous A--B-transition occurs during minimization procedure. The conclusion arises about entropy mechanism of A-form stabilization. The B--A-transition is impossible lower certain temperature for certain salt concentrations. The strong and mobile dehydratant must stimulate the A-form realization. The strong and polymeric dehydrant must stimulate the compactization of macromolecule on the basis of B-form.