Krasnokutskiy S. Molecular structure of nucleic acid monomeric fragments isolated in the low temperature inert matrix

The object of the research of the thesis is nucleosides: thymidine, 2'-deoxyuridine, uridine; a modified nucleoside with antiviral and antitumoral activity - syncytol; sugars: a ribose, 2-desoxyribose; nucleic bases: 1-methyl-uracile, 1-methyl-thimine. The purpose of research: finding-out of a conformation of nucleosides, and also new modified nucleoside with antiviral activity, syncytol. Such research methods and instrumentation as Fourier-transform IR spectroscopy of matrix isolation and quantum chemical calculations by methods of a Hartree-Fock and Moller-Plesset were used in the thesis. The conformational equilibrium of biomoleculas was studied ground of comparative analysis of experimental and theoretical results. Theoretical and practical results of the research are geometrical parameters, vibration spectra of nitrogen bases and sugars and also quantum chemical analysis of a conformational equilibrium of nucleosides; molecular structures of 1-methyluracile, 1-methylthimine, thymidine, uridine, ribose, 2-desoxyribose in an isolated state. The ratio and thermodynamic parameters of different conformers for all studied molecules in an isolated condition are established. The conformations new nucleoside with antiviral and antitumoral activity - syncytol are investigated. Novelty: Fourier-transform IR spectroscopy of matrix isolated molecules (ribose, 2-desoxyribose, thymidine and uridine) and their quantum chemical simulation; a percentage ratio of different conformers for all molecules, which one were studied, and their thermodynamic parameters in an isolated state; in an isolated state a syn-conformation of pyrimidine nucleosides is stabilized by an intramolecular hydrogen binding О5'Н...О2, and the anti-conformation of uridine is stabilized by a hydrogen binding О2'Н...О2. The model of antiviral action of a new nucleoside - syncytol is offered. The results of the thesis have been introduced at mining antiviral drugs on the basis of nucleosides and for the analysis of capabilities of the modern quantumchemical programs, calculations both simulation of processes inside and intermolecular interactions. The field of usage of practical development is a molecular biophysics, medical physics and pharmacology.