I. S. Voiteshenko¹, R. O. Zhurakivsky², L. A. Bulavin¹, D. M. Hovorun^2,3

¹Taras Shevchenko Kyiv National University, Kyiv, Ukraine;
²Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv;
³Institute of High Technologies, Taras Shevchenko Kyiv National University, Ukraine;
e-mail: isvoiteshenko@gmail.com

The physical adequacy of the simplest molecular model “sugar residue (SR) – phosphate group (PG) – SR” of 2′-deoxyribopolinucleotides sugar-phosphate backbone is confirmed at DFT B3LYP/6-31++G(d,p) and DFT B3LYP/6-31G(d,p) of quantum-chemical methods. It is proved that complicacy of the model to the “SR-PG-SR-PG-SR” and higher levels does not noticeably change the numerical values of torsion angles. Also these angles depend negligibly on counterion nature (e.g. Na⁺ to Li⁺, K⁺ or Cs⁺ change) and transition from vacuum to continuum approximation with medium dielectrical values of 1.4, 24.9, and 78.4. It is shown that model loses its adequacy when PG is the end link.