title: Melting of DNA-actinomycin clusters.
abstract: Differential methods of scanning micro-calorimetry and UV spectrophotometry were used for understanding the interaction of natural anti-tumour antibiotic actinomycin D with cluster sites of native and fragmented DNA during thermal melting. At low (micro-molar) concentrations, the actinomycin molecules penetrate into unwound regions of DNA, but not into the double helix. Moreover, they stabilize the fragmented DNA and increase a total melting point. Actinomycin D interacts with fractions of native DNA even at very low concentrations (at the antibiotic/nucleotide ratio of 1:868) and stabilizes the most loose clusters. At high concentrations, it destabilizes the double helix.
authors.affiliation: Institute of Cell Biophysics of Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia. nvekshin@rambler.ru
authors.forename: Nikolai
authors.initials: N
authors.lastname: Vekshin
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000737:chemistry*; D002151:Calorimetry; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D003609:Dactinomycin / Q000737:chemistry*; D009691:Nucleic Acid Denaturation; D013053:Spectrophotometry; D013696:Temperature
chemical_list: D000903:Antibiotics, Antineoplastic; D003609:Dactinomycin; D004247:DNA