[Irradiation of DNA with ultraviolet light: potential changes and mutations]

It is proposed a mechanism of formation of potential changes at UV irradiation of DNA. It consists in the changes of tautomers of nucleotide bases provoked by a simultaneously hydrogen atoms transitions of first and second H-bonds in G-C pair. The reason of such transitions are strong atomic vibrations induced by electronic excitation energy into heat transition and also protons excitation. The probability of different lengthening of h-b-1 bond length from equilibrium one are estimated for two different "temperature" of a small fragment. The possibility of formation of a protonic exciton on DNA Fragments consisting only from G-C pairs is demonstrated. The dispersion law of protonic excitation and its group velocity are obtained. The role of such quasiparticles at potential mutations formation is discussed as soon as the origin of "neighbour effects", i.e. way does depend the mutation ability degree of a given nucleotide nature of neighbouring ones.