title: Molecular basis of chromosome banding. II. The effect of silver and mercury ions on the fluorescence intensity of acranil-DNA complexes.
abstract: Silver and mercury ions are known to react with the bases of nucleic acids in solution. At low cation/base ratios Ag+ has an affinity for GC pairs in DNA, whereas Hg++ is preferentially bound to AT-rich nucleic acids. We have used fluorometry to measure the effect of these cations on the fluorescence intensity of preformed complexes of acranil and DNA in solution. The results are: 1) Ag+ enhances the fluorescence intensity presumably by affecting the dye intercalated in the vicinity of GC-pairs. 2) The addition of Hg++ leads to a quenching of the fluorescence intensity of the complex at low ion/base ratios, suggesting an effect on the dye molecules bound to AT pairs. At high GC-content of the nucleic acid, slight enhancement of the fluorescence intensity occurs with Hg++. 3) With both metals there is a correlation between base content of DNA and effect on the intensity of fluorescence indicating base specificity of the dye-polymer interaction.
mesh_terms: D000166:Acridines / Q000378:metabolism; D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D002417:Cattle; D002875:Chromosomes / Q000032:analysis*; D004247:DNA / Q000032:analysis / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000378:metabolism*; D008628:Mercury / Q000494:pharmacology*; D009690:Nucleic Acid Conformation; D009711:Nucleotides / Q000032:analysis; D011063:Poly A-U / Q000378:metabolism; D012834:Silver / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D013194:Staining and Labeling
chemical_list: D000166:Acridines; D004269:DNA, Bacterial; D005456:Fluorescent Dyes; D009711:Nucleotides; D011063:Poly A-U; D012834:Silver; D004247:DNA; D008628:Mercury