Footprinting studies on the interactions of nogalamycin, arugomycin, decilorubicin and viriplanin with DNA.

DNase I footprinting studies employing several DNA fragments have confirmed that nogalamycin binds preferentially to regions of DNA containing alternating purines and pyrimidines. Arugomycin and viriplanin A, related compounds which contain additional sugar residues at both ends of the molecule, produce similar patterns of nuclease protection though at higher drug concentrations. The pattern induced by decilorubicin, which has charged groups at both ends of the aglycone, differs in many details and this analogue appears to display a modified DNA sequence selectivity. The results have been confirmed by similar studies using DNase II. All four compounds increase the susceptibility of certain adenine residues to modification by diethylpyrocarbonate. The results suggest an intercalative mode of binding for these nogalamycin analogues, and reveals an increased complexity in compounds which can bind to DNA by this mechanism.