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N I Rechkunova

Publications and source records attributed to N I Rechkunova.

At least 37 records · Page 2Linked to original sources
PubMed1993

Interaction of VspI and Tru9I restriction endonucleases with synthetic oligonucleotides.

We describe the properties of two new restriction endonucleases VspI and Tru9I which recognize sequences AT TAAT and T TAA, respectively. The molecular weights, subunit structure and steady-state kinetic constants of these enzymes for native and modified substrates have been determined. We have investigated the interaction of VspI and Tru9I with synthetic oligonucleotides containing modifications either within the recognition sites or around them. These modifications represent the substitution of different DNA deoxyribonucleosides by 1,2-dideoxy-D-ribofuranose, which corresponds to loss of the heterocyclic base while the sugar-phosphate chain remains intact. The effects of the substitutions were analyzed by determining the steady-state kinetic values of the hydrolysis reaction by VspI and Tru9I. The enzymes exhibited Michaelis-Menten kinetics for hydrolyzable substrates. The initial rates (V0) of hydrolysis of modified and unmodified strands of the duplexes varied as a result of these substitutions. The substrates for VspI and Tru9I which contain modifications around the bond to be hydrolyzed or within the complementary nucleosides were unreactive.

Base Sequence↗
PubMed1990

II-Q restriction endonucleases--new class of type II enzymes.

Unique restriction endonucleases Bpu 10l and Bsil have been isolated from Bacillus pumilas and Bacillus sphaericus, respectively. The recognition sequences and cleavage points of these enzymes have been determinated as 5'-CC1TNAGC-3'/3'-GGANT1CG-5' for Bpu 10l and 5'-C1TCGTG-3'/3'-GAGCA1C-5' for Bsil. Restriction endonucleases Bpu 10l and Bsil represent a new class of enzymes which recognize non-palindromic nucleotide sequences and hydrolize DNA within the recognition sequence. Bpu 10l and Bsil recognition sequences may be regarded as quasipalindromic and the enzymes may be designated as type II-Q restriction endonucleases.

Bacillus↗
PubMed1990

[Detection of aquatic microorganisms from the Black Sea--producers of restriction endonucleases].

300 clones of microorganisms isolated at different stations and from different depths in the Black Sea were screened for restriction endonucleases production. The production of restriction endonucleases was found in 17 clones screened. Three of them were identified to be Alteromonas haloplanktis B1. Restriction endonuclease AhaB1 is an isoshizomer of Sau961. An identified Alteromonas haloplanktis clone B8 produces AhaB8I restriction endonuclease the prototype to which is KpnI. Of the clones isolated three are Moraxella species B4 producing MapB4I restriction endonuclease analogous to BanI, three are Bacillus species producing BspB2I and one is Micrococcus lylae 113 producing Mly1131 analogue of NarI, six Moraxella species B6 produce MspB6I. The isolated producer strains may be used for isolation of above mentioned restriction endonucleases.

Bacteria↗
PubMed1988

[Effect of the structure of oligonucleotide substrates on interaction with methylase Eco dam].

The interaction of Eco dam methylase with various synthetic oligonucleotide substrates was investigated. The "imperfect" duplexes contained a normal GATC recognition sequence in one chain of the enzyme recognition site and had some defects in the complementary chain, i.e., the absence of one or several nucleotide residues or the presence of S-methyl thiophosphate groups at the 3'-termini. The 3'-S-methyl thiophosphate residue has the same effect on the methylation of oligonucleotide complexes as does the absence of internucleotide phosphate in the analogous complexes. The presence of both GA dinucleotides in the recognition site is necessary for a productive enzyme-substrate interaction. The experimental data suggest that Eco dam methylase does form a symmetrical enzyme-substrate complex which is similar to that formed by type II restriction enzymes.

Base Sequence↗
PubMed1987

[Chemical synthesis and properties of oligonucleotide substrates for restriction endonuclease BamHI and methyltransferase Eco dam].

Oligodeoxyribonucleotides which form a number of duplexes, containing the recognition sequences for endonuclease BamHI and DNA methylase Eco dam, were synthesised by the phosphotriester approach. Furthermore, synthesis of 3'-phosphorylated oligodeoxyribonucleotides from corresponding S-methyl phosphorothioate triester oligomers is described. The synthetic duplexes are characterized by some defects in the recognition sequences for endonuclease BamHI and methylase Eco dam, viz. nick, absence of an internucleotide phosphate, modifications (including partial single-strandedness) of the recognition site. Interaction of the enzymes with these synthetic substrates was investigated.

Base Sequence↗
PubMed1987

[Substrate specificity of restriction endonuclease VspI].

The recognition sequence and cleavage point of restriction endonuclease VspI have been determined as 5'-AT decreases TAAT. This enzyme is not isoschizomer of any known restriction endonucleases. DNA pBR322 contains a single VspI recognition sequence in position 3539. Therefore this enzyme may be used for cloning DNA in the VspI site in AmpR-gene of pBR322.

Base Sequence↗
PubMed1987

[Specificity of restriction endonuclease VneI].

The recognition sequence and cleavage point of restriction endonuclease VneI have been determined as 5'-G decreases TGCAC. This enzyme is not isoschizomer of any known restriction endonucleases and therefore may be widely used in investigation of DNA structure.

Base Sequence↗
PubMedDate not supplied

[Preparation of photoreactive oligonucleotide duplexes and their application for photoaffinity modification of DNA-binding proteins].

To introduce photoreactive dNTP residues to the 3'-end of a mononucleotide gap, base-substituted photoreactive deoxynucleoside triphosphate derivatives, (5-[N-(2,3,5,6-tetrafluoro-4-azidobenzoyl)-trans-3-aminopropenyl-1]- and 5-(N-[N-(4-azido-2,5-difluoro-3-chloropyridine-6-yl)-3-aminopropionyl]- trans-3-aminopropenyl-1)-2'-deoxyuridine 5'-triphosphates, were used as substrates in the DNA polymerase beta-catalyzed reaction. The resulting nick, containing a modified base at the 3'-end, was sealed by T4 phage DNA ligase. This approach enables the preparation of DNA duplexes bearing photoreactive groups at predetermined position(s) of the nucleotide chain. Using the generated photoreactive DNA duplexes, the photoaffinity modifications of DNA polymerase beta and human replicative protein A (hRPA) were carried out. It was shown that DNA polymerase beta and hRPA subunits were modified with the photoreactive double-stranded DNA considerably less effectively than by the nicked DNA. In the case of double-stranded DNA, the hRPA p70 subunit was preferentially labeled, implying a crucial role of this subunit in the protein-DNA interaction.

DNA Polymerase beta↗