Infrared linear dichroism of oriented DNA-ligand complexes prepared with the wet-spinning method.
Oriented DNA films prepared by the wet-spinning technique have been complexed with several ligands: the anthracycline antibiotic violamycin BI, the dipeptide L-carnosine, and the oligopeptide antibiotic netropsin. The formation of the DNA-ligand complexes is accompanied by dramatic changes of the conformational flexibility of DNA. The B-A transition which occurs usually between 80% and 70% relative humidity (RH) is more or less suppressed by the ligands. Violamycin BI at a total ligand per DNA base pair ratio, rt, of approximately 0.03 and L-carnosine at rt approximately 1.5 inhibit the B-A transition of approximately 18 and approximately 0.25 base pairs per ligand molecule, respectively. Netropsin at rt = 0.2 induces a very stable B-DNA even at rather low RH (23%). The total hydration of this complex is significantly higher than for a drug-free DNA film. Netropsin-DNA complexes at rt of 0.02 and 0.01 result in an inhibition of approximately 45 base pairs per drug molecule with respect to the B-A transition.
D000617:Aminoglycosides; D000818:Animals; D000900:Anti-Bacterial Agents; D002336:Carnosine; D002417:Cattle; D004247:DNA; D007700:Kinetics; D008024:Ligands; D009429:Netropsin; D009690:Nucleic Acid Conformation; D013055:Spectrophotometry, Infrared; D013950:Thymus Gland
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D008024:Ligands; C010806:violamycins; D009429:Netropsin; D002336:Carnosine; D004247:DNA