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E Bubienko

Publications and source records attributed to E Bubienko.

5 recordsLinked to original sources
PubMed1985

Interactions of diastereomeric tripeptides of lysyl-5-fluorotryptophyllysine with DNA. 2. Optical, 19F NMR, and strand cleavage studies of apurinic DNA complexes.

The interactions of the diastereomers lysyl-5-fluoro-L-tryptophyllysine and lysyl-5-fluoro-D-tryptophyllysine with apurinic DNA have been examined as a model for the action of DNA repair enzymes. The binding characteristics of the tripeptide diastereomers to DNA, modified to contain approximately 5% apurinic sites, were studied by measuring 19F NMR parameters, fluorescence quenching, and activity in promoting single-strand cleavage of plasmid DNA. The affinities of each of the peptides to apurinic DNA are similar to those for native DNA. However, the 19F NMR chemical shift and relaxation behavior indicates that both diastereomers form complexes with apurinic DNA that are distinct from those formed with native DNA. In addition, the 19F NMR measurements differ for the L-Trp and D-Trp complexes with apurinic DNA. In spite of these differences, when either of the tripeptide diastereomers is incubated with plasmid DNA containing apurinic sites, no difference in the rate of single-strand cleavage of the DNA is detectable.

Animals↗
PubMed1981

Sequence and structure in double-stranded ribonucleic acid: (A-G-C-U)2 and (A-C-G-U)2.

Comparative studies of the thermally induced helix--coil transition in ribosyl (A-G-C-U)2 and (A-C-G-U)2 are described. Ordered structures form at low temperatures where the ribofuranose rings adopt the 3'-endo conformation and both oligomer helices have base-paired stacking arrangements qualitatively similar to the A-RNA family configuration. Especially for (A-C-G-U)2, there is a lack of quantitative agreement between the A-family base overlap and the 1H NMR data; ring-current and atomic diamagnetic anisotropies using A-form structures fail to predict five of the seven aromatic C--H resonances within 0.2 ppm. The NMR results are in better agreement with the A form for (A-G-C-U)2. For both oligomers, the changes in chemical shift for the anomeric (H1') resonances indicate substantial (greater than or equal to 20 degrees) changes in the average glycosidic torsion angle upon base pairing and stacking for the adenosine and cytidine residues; this angle in uridine and guanosine residues must change only slightly.

Base Sequence↗