[Interaction specificity of violamycin BI and BII with DNA using the hyperchromic spectra method]

Interaction specificity of the anthracycline antibiotics violamycin BI and violamycin BII in respect to A.T and G.C pairs was investigated. For comparison denaturation of complexes with A.T and G.C specific ligands distamycin A and actinomycin D are presented. Making use of the least squares hyperchromic spectra measured in the course of thermal denaturation were partitioned into the components corresponding to the melting of A.T and G.C base pairs and dissociation of ligand. The mutual dependence of AT and GC denaturation allows one to draw conclusions about specificity of interaction. In case of both violamycins only slight preference of interaction with AT-rich regions was detected. The dissociation of violamycin BII in the latest stage of thermal denaturation was found to be cooperative.