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V I Poltev

Publications and source records attributed to V I Poltev.

81 records · Page 5Linked to original sources
PubMedDate not supplied

[The mechanism of tautomeric transitions of nucleic acid bases with limited access to water molecules].

Pathways of tautomeric transformations of nucleic acid bases have been considered in the conditions when only few separate water molecules can interact with the bases. Field ionization mass-spectrometric study has demonstrated that substitution of one of the labile hydrogen atoms for deuterium takes place when thymine (or 1-methylthymine) interacts with heavy water in vacuo. This observation was explained by a supposition that a transient water-thymine complex is formed and then tautomeric transition of the base occurs via double proton transfer along hydrogen bonds. Calculations of the interaction energy between base and water molecules allowed us to suggest the structure of such a complex in which water molecule lays in the plane of the base. Formation of such complexes during biosynthesis of nucleic acids can give rise to point errors, probability of their appearance being dependent on the structure and properties of a macromolecular DNA-enzyme-nucleotide complex.

Hydrogen Bonding↗
PubMedDate not supplied

[Molecular mechanisms of mutations, arising during formation of 8-hydroxyguanine in DNA].

To reveal the molecular mechanisms of genotoxic effects of oxidation and irradiation, molecular mechanics computations were performed for double-helical olygonucleotides with 8-oxoguanine:adenine (OG.A) pairs in two configurations. Substitution of a T.A pair by OG(syn).A one results in minor changes of intramolecular interaction energy and of the conformational parameters of helixes. Nearly all the interproton distances in low-energy conformations of d(CCACTAOGTCACC):d(GGTGAATAGTGG) with a OG(syn).A pair are within the limits determined from NMR data. These results confirm the suggestion that such pairs can be formed in nucleic acid biosynthesis. The computations have shown that the interaction energies in the minima for duplexes with OG(anti).A and OG(syn).A pairs differ from one another by only 1 to 3 kcal/mol. This difference depends on the nucleotide context. These results allow one to suppose that the configuration of the OG.A pair in the double helix and, as a consequence, the induced mutation probability depends on interactions with its environment (neighboring base pairs and solvent).

Base Sequence↗
PubMedDate not supplied

[Genotoxic modification of nucleic acid bases and biological consequences of it. Review and prospects of experimental and computational investigations].

The review is presented of experimental and computational data on the influence of genotoxic modification of bases (deamination, alkylation, oxidation) on the structure and biological functioning of nucleic acids. Pathways are discussed for the influence of modification on coding properties of bases, on possible errors of nucleic acid biosynthesis, and on configurations of nucleotide mispairs. The atomic structure of nucleic acid fragments with modified bases and the role of base damages in mutagenesis and carcinogenesis are considered.

Alkylation↗