[The influence of complementary base pair interactions on secondary structure formation and conformational transitions in polynucleotides].

The calculations have been carried out of interaction energy between complementary base pairs of nucleic acids in the function of conformational parametres of double helix (Arnott's parameters) by the method of atom-atom potential functions. Interaction energy as a function of conformational parametres is valley-like and varies little along the bottom of the valley. The regions of interaction energy minima are compared with experimentally determined conformational parametres of nucleic acid double helices. On the basis of calculation results the pathways of conformational transitions between different forms of double-helical polynucleotides are discussed.