title: Effect of cationic drugs on suprahelical organization of DNA.
abstract: Interaction of a minor groove-binding drug Hoechst-33258, and an intercalating drug, proflavin, with the PSI(+) form of DNA, was studied using CD spectroscopy. Both drugs are shown to relax the suprahelical organization of DNA, leading to the formation of a B-like structure, above a certain drug to phosphate ratio. However, unlike proflavin, Hoechst-33258 brings about further structural changes after formation of the B-like structure whereas proflavin does not. A reversal of the CD signal in the 300-450-nm spectral region is also observed with Hoechst-33258, indicating a change in the handedness of the suprahelical organization of DNA. To the best of our knowledge, drug-mediated changes as presented in this paper have not been reported so far.
authors.affiliation: Centre for Cellular and Molecular Biology, Hyderabad, India.
authors.forename: K G
authors.initials: KG
authors.lastname: Krishna
authors.forename: T K
authors.initials: TK
authors.lastname: Kumar
authors.forename: M W
authors.initials: MW
authors.lastname: Pandit
mesh_terms: D000818:Animals; D001665:Binding Sites; D006690:Bisbenzimidazole / Q000494:pharmacology; D002412:Cations; D002417:Cattle; D002942:Circular Dichroism; D004278:DNA, Superhelical / Q000737:chemistry / Q000187:drug effects*; D066298:In Vitro Techniques; D011370:Proflavine / Q000494:pharmacology
chemical_list: D002412:Cations; D004278:DNA, Superhelical; D011370:Proflavine; D006690:Bisbenzimidazole