Interaction of DEAP fluoranthene (RMI 9563 DA) with DNA and metaphase chromosomes.

A fluorescent compound, DEAP fluoranthene (a tilorone cogener), has been suggested to bind to DNA by intercalation. The interaction of this drug with natural and synthetic DNAs and human metaphase chromosomes has been investigated in detail. DEAP fluoranthene shows a slight A-T preference in binding to DNA and was also found to change the topological winding number of superhelical DNA. These data, and the determined unwinding angle of 27 degree for DEAP fluoranthene, strongly support an intercalation mode of binding for this drug to DNA. DEAP fluorescence is minimally quenched when intercalated between A-T base pairs and maximally quenched when interacting with G-C base pairs. DEAP fluoranthene was found to produce bright fluorescent bands on human metaphase chromosomes identical to those produced by quinacrine. The solution data on DEAP fluoranthene interaction with DNA can be used to rationalize the production of differential banding patterns on chromosomes by DEAP fluoranthene in which the drug reports underlying DNA sequence arrangement of the metaphase chromosome.