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V N Sil'nikov

Publications and source records attributed to V N Sil'nikov.

18 recordsLinked to original sources
PubMed2004

Interaction of replication protein A with photoreactive DNA structures.

A new photoreactive oligonucleotide derivative was synthesized with a perfluoroarylazido group attached to the 2'-position of the ribose fragment of the 5'-terminal nucleotide. Using this conjugate, photoreactive DNA duplexes were produced which contained single-stranded regions of different length, single-stranded breaks (nicks), and also ds duplex with a photoreactive group inside one of the chains. These structures imitate DNA intermediates generated at different stages of DNA replication and repair. The interaction of replication protein A (RPA) with the resulting DNA structures was studied using photoaffinity modification and gel retardation assay. Independently of the DNA structure, only the large subunit of RPA (p70) was crosslinked to photoreactive DNAs, and the intensity of its labeling increased with decrease in the size of the single-stranded region and was maximal in the case of the nick-containing DNA structure. By gel retardation, the most effective binding of RPA to this structure was shown, whereas the complexing of RPA with DNA containing the unmodified nick and also with the full duplex containing the photoreactive group inside the chain was significantly less effective. The data suggest that RPA should be sensitive to such damages in the double-stranded DNA structure.

Azides↗
PubMed2000

[Chemical ribonucleases. 2. Design and hydrolytic properties RNase mimetics based on diazabicyclo[2.2.2]octane with various positive charges].

A procedure was proposed allowing one to synthesize RNA mimics on the basis of conjugates of diazabicyclo[2.2.2]octane with imidazole bearing a varying number of positive charges (nDm series, where n is the number of positive charges at neutral pH, m is the code of an imidazole-containing fragment of the catalytic domain: 1, histamine; 2, histidine methyl ester). The hydrolytic activity of six compounds of this series was studied under physiological conditions using in vitro transcript of human mitochondrial tRNA(Lys) as a substrate. It was shown that the rate of RNA hydrolysis with nDm conjugates rises with an increase in the number of positive charges: an approximately 30-fold acceleration of hydrolysis was observed with an increase in the total charge of the construct from +2 to +4.

Bridged Bicyclo Compounds, Heterocyclic↗
PubMed2000

[Chemical ribonucleases. 3. Synthesis of organic catalysts of hydrolysis of phosphodiester bonds based on quaternary salts of 1,4-diazabicyclo(2.2.2)octane].

On the basis of imidazole and bisquaternary salts of 1,4-diazabicyclo[2.2.2]octane, a number of highly effective catalysts of the nDm series (here, n is the number of positive charges at neutral pH values and m is the digital code of the catalytically active fragment: 1, histamine, and 2, histidine methyl ester) were synthesized for the cleavage of the phosphodiester bonds in ribonucleic acids. A general method for the synthesis of chemical ribonucleases was suggested, which helps vary both the number of positive charges in their RNA-binding domain and the catalytic center. By the example of hydrolysis under physiological conditions of the in vitro transcript of tRNA(Lys) from human mitochondria, it was shown that the RNA cleavage rate with the nDm conjugates increases approximately 30-fold along with the increase in the number of positive charges from two to four.

Humans↗
PubMed1999

[Synthetic ribonucleases. 1. Synthesis and properties of conjugates, containing an RNA-binding fragment based on lysine residues and an RNA hydrolyzing fragment, bearing an imidazole residue].

A series of RNA-hydrolyzing constructions was synthesized on the basis of peptide-like molecules containing residues of L-lysine, histamine and histidine methyl ester. These were shown to hydrolyze RNA effectively at neutral pH values. The in vitro transcript of tRNA(Lys) from human mitochondria and a tRNA-like fragment of RNA of Turnip Yellow Mosaic Virus were used in the experiments. Our chemical RNases quantitatively depolymerize some definite sequences (CA > or = UA > CG >> UC, CC, or CU) in both RNA molecules under optimum conditions. Moreover, no other sites were affected and no statistical hydrolysis was observed even after prolonged RNA incubation with the compounds of this series. The depolymerization rate of the RNA substrates exhibits a complex dependence on the concentration of ions of monovalent metals and on the concentration of the artificial ribonucleases.

Humans↗
PubMed1987

[Modification of nucleic acids in stabilized complementary complexes. II. Effectiveness and direction of alkylation of dodecadeoxyribonucleotide d(pA-A-C-C-T-G-T-T-T-G-G-C) with 4-(N-2-chloroethyl-N-methylamino)benzylidene derivative of the complementary heptanucleotide d(pC-C-A-A-A-C)-A containing a N-(2-hydroxyethyl)phenazinium residue at the 5'-end].

Modification of dodecadeoxyribonucleotide d(pA-A-C-C-T-G-T-T-T-G-G-C) (I) with a heptanucleotide 4-(N-2-chloroethyl-N-methylamino)benzylidene (RCI) derivative d(pC-C-A-A-A-C) ARCI (II) and with similar reagent (III) bearing an additional 5'-terminal N-(2-hydroxyethyl)phenazinium residue (Phn) has been unvestigated. Both reagents (II) and (III) alkylated dodecanucleotide (I) mainly at the 5'-terminal phosphate, Phn residue not affecting specificity of the alkylation. Stabilization of the complementary complex target oligonucleotide-oligonucleotide derivative by the Phn group resulted in substantial increase of efficiency and rate of the intracomplex alkylation of the dodecanucleotide.

Alkylation↗
PubMedDate not supplied

Synthesis of azidoaniline derivatives of oligonucleotides and investigation of their photochemical behavior.

A series of aryl azides, p-N3C6H4NH(CH2)nNH2 with n = 2-6, have been synthesized and used to prepare oligonucleotide derivatives carrying photoreactive the p-azidoaniline residue. Reactive moieties have been coupled to the 5'-terminal phosphate of d(pGATACCAA) [compounds IV(b), IV(c), and IV(e) with n = 3, 4, and 6, respectively] and of d(pGCC) [compound V(b) with n = 3] via a phosphoamide bond. Irradiation at wavelengths over > 300 nm of IV(b) and V(b) (n = 3) resulted in cleavage of the P-N bond. However, under the same reaction conditions, the P-N bond remained intact for compounds containing longer spacers [IV(c) and IV(e)]. Intraduplex reaction of the latter derivatives with d(GGTATCp)NH(CH2)6NH2 resulted in cross-linking dependent on the presence of an aliphatic amino group. The results obtained have demonstrated that the azidoaniline derivatives of oligonucleotides capable of the affinity modification of a specific target can be prepared. However, the sufficiently long aliphatic spacer group is necessary to prevent P-N bond cleavage within the photoreactive oligonucleotide.

Alanine↗
PubMedDate not supplied

[Monomers for oligonucleotide synthesis with linkers carrying reactive residues: I. Synthesis of deoxynucleoside derivatives with methoxyoxalamide groups in heterocyclic bases].

A number of monomers for the standard phosphoamidite oligodeoxynucleotide synthesis that carry reactive methoxyoxalamide groups attached to the thymidine, 2'-deoxycytidine, and 2'-deoxyadenosine heterocyclic bases were prepared. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.

Amides↗
PubMedDate not supplied

[Highly efficient site-directed RNA cleavage by imidazole-containing conjugates of antisense oligonucleotides].

A method has been suggested for the synthesis of conjugates of oligodeoxyribonucleotides with chemical constructs mimicking ribonuclease A active center for directed fragmentation of RNA. The method is based on the sequential addition of linker group, 9-(methylamino)anthracene, to 5' or 3' terminal phosphate of oligonucleotide and then imidazole-containing construct by cycloaddition reaction. The conjugates of oligonucleotides complementary to regions 44-61 (2B-R) and 60-76 (1C-R) of yeast phenylalanine tRNA demonstrated ability to cleave tRNA(Phe) under physiological conditions preferably at the sole phosphodiester bond (C63-A64 for 2B-R and C56-G57 for 1C-R, respectively). The half-time of tRNA(Phe) hydrolysis in the presence of 2B-R conjugate was 30 min at 2B-R concentration of 10 microM and several minutes at conjugate concentration of 50 microM.

Base Sequence↗
PubMedDate not supplied

[Chemical ribonucleases. 4. Analysis of the fragment structure of chemical ribonucleases based on 1,4-diazabicyclo[2.2.2]octane].

Artificial ribonucleases of the ABLkCm series were synthesized. They consist of a lipophilic alkyl radical (Et, n-C14H29, or C15H31) A, an "RNA-binding domain" B (bisquaternary salt of 1,4-diazabicyclo[2.2.2]octane), a "catalytic domain" Cm [histamine (C1) or histidine (C3) residue], and a "linker" Lk that joins the "domains" B and Cm [here, k is the number of methylene units (one or three) in the linker]. The effect of the "domain structure" on the catalytic properties of the chemical ribonucleases was analyzed using seven compounds of this series (ABL1C1, ABL3C1, ABL3C3, AC1, AB, BL2, and BL3C3). The catalytic activity of the compounds was assessed in the reaction of hydrolysis of the in vitro transcripts of human tRNA(Lys) and yeast tRNA(Asp) under physiological conditions. It was shown that only chemical ribonucleases that involve all the fragments of the ABLkCm construct can hydrolyze the substrate tRNA at a high rate (90% of tRNA is hydrolyzed for 10 h at 37 degrees C). The activity of the compounds is largely determined by the presence of a long lipophilic radical linked to 1,4-diazabicyclo[2.2.2]octane and a long linker, which joins the RNA-hydrolyzing and RNA-binding fragments. The results indicate an important role of hydrophobic interactions in the acceleration of the RNA hydrolysis reaction. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2002, vol. 28, no. 4; see also http://www.maik.ru.

Catalysis↗
PubMedDate not supplied

[Kinetic parameters of hydrolysis of CpA and UpA sequences in an oligoribonucleotide by compounds functionally mimicking ribonuclease A].

Kinetic parameters of cleavage of CpA and UpA sequences in an oligoribonucleotide under the action of artificial ribonuclease ABL3C1 were measured. The compounds were built of RNA-binding domain B, catalytic fragment C, linker L3 comprising 3 methylene groups, and aliphatic fragment A. The rate of cleavage of phosphodiester bonds in CpA sequence within decaribonucleotide UUCAUGUAAA was shown to be 3.4 +/- 0.2 times higher than in UpA sequence. The rate of cleavage of phosphodiester bonds were found to depend on substrate length: a thousandfold increase in cleavage rate constant was observed for CpA sequence in decaribonucleotide as compared with diribonucleotide monophosphate CpA. A slight decrease in the cleavage rates was observed for the reactions proceeding in different buffers at pH 7.0: imidazole > HEPES > phosphate > cacodylate. At the same time, the ratio of cleavage rates for CpA and UpA sequences remained constant.

Aza Compounds↗