Comparative Binding of Ethidium and Three Azido Analogs to Dinucleotides: Affinity and Intercalation Geometry
- 1 July 1983
- journal article
- research article
- Published by Wiley in European Journal of Biochemistry
- Vol. 134 (1) , 163-173
- https://doi.org/10.1111/j.1432-1033.1983.tb07547.x
Abstract
Geometrical and thermodynamic information was obtained from theoretical analysis of both visible and 1H NMR spectroscopic binding isotherms of ethidium and 3 photoactivatable derivatives (8-azido-ethidium, 3-azido-ethidium and 3,8-diazido-ethidium) to self-complementary ribodinucleosides. Interaction with pyrimidine(3-5'')-purine sequences is well accounted for by multicomponent equilibria involving self-association of the dyes in oligomers, formation of 1:1 and 2:1 (nucleoside:dye) complexes. This model provided evidence for intercalation of all dyes, though with weaker affinity in the case of diazido-ethidium (2 .times. 106 M-2 vs 6 .times. 107 M-2). Moreover 3-azido-ethidium was shown to intercalate into CpG with its phenyl group lying in the major groove of the minihelix. This geometry is inverted with respect to that of all other compounds. Visible and 1H NMR techniques independently provided similar results (intercalation, affinity constants) therefore supporting this stepwise model. Interaction of all dyes with purine(3''-5'')pyrimidine sequences is not intercalative, even at low temperature (4.degree. C), but is well described by self-association of the dyes and formation of 1:1 (nucleoside:dye) complexes. Regarding the reversible DNA intercalation process, these studies show that 8-azido-ethidium is the only photoactivatable derivative which behaves exactly as ethidium. Therefore 8-azido-ethidium can be used as a covalent probe to investigate the DNA-related cytotoxic effects of ethidium.This publication has 45 references indexed in Scilit:
- Comparative studies of the binding of ethidium bromide and its photoreactive analogs to nucleic acids by fluorescence and rapid kineticsBiochemistry, 1980
- Covalent binding of ethidium azide analogs to Salmonella DNA in vivo: Competition by ethidium bromideBiochemical and Biophysical Research Communications, 1979
- Induction of respiratory deficient mutants in Saccharomyces cerevisiae by mono- and diazido analogs of ethidiumMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 1977
- Visualization of drug-nucleic acid interactions at atomic resolutionJournal of Molecular Biology, 1977
- Production of frameshift mutations in salmonella by a light sensitive azide analog of ethidiumMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 1976
- Hydrogen-bonded complexes of the ribodinucleoside monophosphates in aqueous solution. Proton magnetic resonance studiesBiochemistry, 1976
- Methods for detecting carcinogens and mutagens with the salmonella/mammalian-microsome mutagenicity testMutation Research/Environmental Mutagenesis and Related Subjects, 1975
- Bypass by photoaffinity labeling of blocked metabolic activation of ethidium: Confirmation of the role for covalent ethidium attachment in mitochondrial mutagenesisBiochemical and Biophysical Research Communications, 1975
- Selective covalent binding of an ethidium analog to mitochondrial DNA with production of petite mutants in yeast by photoaffinity labelingJournal of Molecular Biology, 1975
- Ethidium bromide induced mutation of yeast mitochondria: Complete transformation of cells into respiratory deficient non-chromosomal “petites”Biochemical and Biophysical Research Communications, 1968