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Biomedical subjects

R M Wartell

Publications and source records attributed to R M Wartell.

9 recordsLinked to original sources
PubMed1978

Conformational features of distamycin-DNA and netropsin-DNA complexes by Raman spectroscopy.

The binding of distamycin and netropsin to duplex DNA has been studied by Raman spectroscopy. Several changes occur in the Raman spectra of these drugs upon binding DNA. These changes were analyzed by assigning specific motions to the observed Raman bands through the use of molecular subunits of the drugs and normal mode calculations. Our analysis indicates that pyrrole ring and peptide group vibrations are altered upon binding to DNA. The environments of the pyrrole ring methyl groups are not affected by the binding. These data provide physical evidence consistent with a binding model in which the methyl groups on the pyrroles project away from the DNA and the peptide N-H groups form hydrogen bonds with the DNA.

Animals↗
PubMed1977

The transmission of stability or instability from site specific protein-DNA complexes.

Theoretical calculations were made to determine the influence of side specific 'melting' and 'stabilizing' proteins on the thermal stability of nearby base pairs (bp). A DNA sequence 999bp. long containing the 123 bp. lactose operon control region in the center was examined. Melting curves of base pairs near the binding sites of the catabolite activator protein, CAP, the lactose repressor, and RNA polymerase were calculated in the absence and presence of each protein. The empirical loop entropy model of the helix-coil transition of DNA was employed. Calculations show that melting and stabilizing proteins alter the tm of base pairs 20 to 100 bp-away. The magnitude and range of the effect is strongly influenced by the base pair composition and sequence of the protein site and the immediately adjacent DNA regions.

Binding Sites↗
PubMed1975

Transmission of stability (telestability) in deoxyribonucleic acid. Physical and enzymatic studies on the duplex block polymer d(C15A15) - d(T15G15).

The properties of the duplex block polymer d(C15A15) - d(T15G15) were examined by thermal denaturation and nuclease susceptibility studies in the absence and presence of drugs (actinomycin and netropsin) which bind specifically to only one end of the block polymer. The nucleotide composition of one region of this synthetic double-helical DNA affected the properties of a contiguous but remote region. Furthermore, the binding of actinomycin influenced the properties of both the binding and nonbinding regions. These findings suggest a mechanism for gene regulation at a distance.

Adenosine Monophosphate↗
PubMed1975

The compatibility of netropsin and actinomycin binding to natural deoxyribonucleic acid.

The simultaneous binding of netropsin and actinomycin to four natural DNAs was studied to determine the influence of one ligand on the binding of the other. Actinomycin binds specifically to GC sites, whereas netropsin binds specifically to AT sites. Spectral titrations, thermal denaturation, and analytical buoyant density centrifugation were employed to measure the binding interference of these drugs. The binding of actinomycin to DNA was decreased by the presence of netropsin. Increasing the GC content of the DNA resulted in a decreased effect of netropsin on actinomycin binding. Quantitative analysis of the binding parameters indicated that netropsin and actinomycin can bind in close proximity along the DNA chain. Supercoiled DNA gave the same result as linear DNA. These results imply that DNA can absorb alterations in conformation within a short distance.

Anti-Bacterial Agents↗