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A A Baev

Publications and source records attributed to A A Baev.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

[Specific cleavage of glycosylyl denatured DNA of T2 and T4 phages adjacent to the oligothymidilic or oligoadenylic sequences].

A method of complementarily directed alkylation with following elimination of the alkylated bases and with DNA cleavage at apurinic sites was used for specific fragmentation of glucosylyl DNA of T2 and T4 phages. It was shown that denatured glucosylyl T2 and T4 DNA's are modified by alkylating derivatives of hexaadenylate and heptauridylilate. The extent of alkylation reached the maximum and then stopped. The extent of elimination and chain cleavage corresponded to that of alkylation. Treatment of DNA after alkylation with (Ap)5ARCl under condition of saturation at 20 degrees gives 572 +/- 28 fragments from T4 DNA with 200--25,000 nucleotides long and 578 +/- 33 fragments from T2 DNA. Alkylation under condition of DNA saturation with (Ap)5ARCl at 40 degrees leads to 138 +/- 15 fragments from T4 DNA and 170 +/- 16 fragments from T2 DNA. Characteristics of the fragments obtained are given.

Adenosine Monophosphate↗
PubMedDate not supplied

[Isolation and properties of DNA-cytosine methyltransferase from Escherichia coli C].

The method of isolation and partial purification of DNA-cytosine-methyltransferase (DC-methylase) from E. coli C is described. The enzyme underwent approximately 100-fold purification. The obtained preparation of DC-methylase can be additionally considerably purified by sedimentation in sucrose gradient. Native molecular weight of DC-methylase from E. coli C. is 70,000. The activity of enzyme does not depend on the Mg2+ ions. DC-methylase E. coli C provides DNA of lambda phage in vitro with full resistance against restriction endonuclease EcoRII. In DNA methylated by DC-methylase the modified cytosine, mainly in C-MC and C-MC-T sequences, corresponds to the pyrimidine sequences of specific site EcoRII. DNA of lambda.B phage contains approximately 80 sites for modification by DC-methylase E. coli C. The results obtained point to the same specificity in vitro of DNA-cytosine-methylase E. coli C and DNA-methylase EcoRII.

Binding Sites↗
PubMedDate not supplied

[Identification of bacterial clones that encode cow's caseins by direct immunological screening of the cDNA library].

A sensitive immunoassay was used to identify recombinant DNA plasmids carrying cDNA fragments of bovine caseins in the cDNA library from rRNA of bovine mammary glands. Colonies grown on nitrocellulose filters were lysed in situ and proteins from the lysates were blotted onto CNBr-activated filter paper. Antigens covalently bound to the CNBr-activated paper or bound to the nitrocellulose filters were detected by reaction with antiserum to caseins, followed by 125I-labeled protein A from Staphylococcus aureus and autoradiography. Four clones were positive among 5400 bacterial clones of the cDNA library--al, b2, b5, h7. Molecular weights of chimeric proteins pre-beta-lactamase:casein synthesized in Escherichia coli were determined by immunoblotting. Colony hybridization and DNA sequence analysis showed that clone b5 contained cDNA fragment of bovine kappa-caseins and clone h7 cDNA fragment of beta-casein. The last clone was designated pKcas beta-7.

Animals↗