Potyahaylo A. Proton mobility in model protein-nucleic acid and nucleic acid-nucleic acid complexes and its possible biological significance

Physico-chemical properties of model protein-nucleic acid and nucleic acid-nucleic acid complexes determining proton mobility are investigated by semi- and non-empirical quantum chemical methods, UV and NMR spectroscopies, proton buffer capacity method. For the first time elementary molecular means of control over nucleotide bases' status and thermo dynamical stability of their Watson-Crick pairs. A conclusion was drawn that even at the level of point contacts protein-nucleic acids recognition may occur not only according to classic conformational scenario but be accompanied by a change in nucleotide base status, that is to touch their chemical structure. New molecular mechanisms of point mutagenesis resulting from prototropic tautomerism of nucleotide bases are proposed. Nature of structural transitions in poly(C) and poly(dC) caused by their protonation was established. Non-canonical intramolecular H-bonds were fixed in 6-azaCyd and in single-stranded poly(A), poly(C) and poly(dC). Sequences of acidity and basicity of 42 modified nucleotide bases are obtained.