Biomedical subjects

I M Kolomiets

Publications and source records attributed to I M Kolomiets.

3 recordsLinked to original sources

PubMedDate not supplied

UV spectra of guanine methyl and glycosyl derivatives and their transformations induced by interactions with amino acids via carboxylic group in dimethylsulfoxide.

UV absorption spectra of guanine derivatives m9Gua, m(2)2,9Gua, m1Gua, m(2)1,7Gua, m3Gua, G, dG, m1G, m2G, m7G, as well as guanine analogue isoGua were studied in anhydrous dimethylsulfoxide (DMSO). Changes in UV absorption spectra of guanine derivatives in the presence of amino acid derivatives with neutral carboxylic group (ac-Asp, ac-Glu, ac-Gly, ac-Asp-OMe) or deprotonated carboxylic group (NaAc, f-Gly-ONa) were investigated and interpreted. The m1Gua and m7Gua derivatives were shown to exist as the N9H tautomers in anhydrous DMSO. The majority of examined guanine derivatives were determined to interact with deprotonated carboxylic group only, except of m7G, isoGua and m3Gua, which are able to form complexes with neutral carboxylic group as well.

Amino Acids↗

PubMedDate not supplied

Recognition modes of hypoxanthine, xanthine and their derivatives by amino acid carboxylic group: UV spectroscopic and quantum chemical data.

UV absorption spectra of Hyp, Xan, their nucleosides and methyl derivatives were studied in anhydrous dimethylsuloxide and the changes in these spectra on the interactions with neutral and deprotonated carboxylic groups of amino acids were traced. By the semiempirical quantum-chemical method MNDO/H it was shown, that interaction with carboxylate-ion fixes Hyp as the rare N7H enolic tautomer and converts Xan into its N9H diketo tautomeric form with a probable admixture of the N7H O6-enolic form. Significant changes in the UV spectra of Xan, m3Xan, m9Xan and X under interaction with carboxylate-ion are determined by essential contribution to complex formation of proton transfer from bases to ligands, m9Xan and X proving to be slightly protonated even by the solvent. The methylation of the N7 position in m7I and m7X was established to result in the practical absence of their interactions with carboxylate-ion and initiation of a new ability of forming complex with the neutral carboxylic group. Substitution of the C8H group by N in 8-azaXan does not change the interaction specificity of the base with two forms of carboxylic group.

Amino Acids↗

PubMedDate not supplied

Dimer linkage structure in retroviruses: models that include both duplex and quadruplex domains.

Genome of all known retroviruses consists of two identical molecules of RNA, which are non-covalently linked. The most stable contact site between two RNA molecules is located near their 5' ends. The molecular interactions in the dimer linkage structure (DLS) in mature virions are currently unknown. Recently we suggested that the dimer linkage structure in human immunodeficiency virus 1 (HIV-1) contains both duplex and quadruplex domains and proposed a model of DLS in HIV-1Mal (Central African virus). In this paper we showed that similar models can be also built for HIV- 1Lai, a representative of the North-American and European viruses. One of the double-stranded domains in the model structures represents either an extended duplex formed by different pathways (through base pair melting and subsequent reannealing or by a recombination mechanism) or kissing loop complex. The quadruplexes contain both G- and mixed tetrads, for example, G.C.G.C or A.U.A.U. Phylogenetic analysis of 350 isolates from NCBI database showed that similar models of DLS are predictable practically for all HIV-1 isolates surveyed. A model of dimer linkage structure in Moloney murine sarcoma virus (MuSV) is also presented. The structure includes a duplex formed by the palindromic sequences and several quadruplexes.

Animals↗