title: Voltammetric and electrochemical gravimetric selective detection of interactions between Tl(I) and guanine and the influence on activity of DNA drug-intercalators.
abstract: The interactions of Tl(I), a well known toxic species, with selected oligonucleotides were examined. The oligonucleotide sequences selected for the investigation were taken from gene hOGG1 responsible for repairing of DNA damage. Cyclic voltammetry was particularly useful, since nitrogen N-7 in guanine can be electrooxidized while its binding with Tl(I) leads to the loss of electroactivity. So, this selected interaction could be quantitatively used in drawing Scatchard's plot and calculating the binding constants and the number of active sites in guanine molecules occupied by one metal ion. Further, we have shown that the presence of Tl(I) leads to a decrease in activity of doxorubicin (DOX), a popular anticancer drug, vs. DNA. The obtained circular dichroism (CD) spectra and the measurements with an electrochemical quartz crystal microbalance (EQCM) led to a conclusion that in the presence of monovalent thallium cations the DNA double helix was neither damaged/oxidized nor its conformation changed substantially.
authors.affiliation: Faculty of Chemistry, University of Warsaw, Pasteura 1, PL 02-093 Warsaw, Poland. anowicka@chem.uw.edu.pl
authors.forename: Anna M
authors.initials: AM
authors.lastname: Nowicka
authors.forename: Marcin
authors.initials: M
authors.lastname: Mackiewicz
authors.forename: Edyta
authors.initials: E
authors.lastname: Matysiak
authors.forename: Beata
authors.initials: B
authors.lastname: Krasnodebska-Ostrega
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Stojek
mesh_terms: D001667:Binding, Competitive; D002414:Cations, Monovalent; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D045647:DNA Glycosylases / Q000737:chemistry; D004317:Doxorubicin / Q000737:chemistry*; D055664:Electrochemical Techniques; D006147:Guanine / Q000737:chemistry*; D006801:Humans; D007364:Intercalating Agents / Q000737:chemistry*; D007700:Kinetics; D009841:Oligonucleotides / Q000737:chemistry*; D058525:Quartz Crystal Microbalance Techniques; D013793:Thallium / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D002414:Cations, Monovalent; D007364:Intercalating Agents; D009841:Oligonucleotides; D006147:Guanine; D004317:Doxorubicin; D004247:DNA; D013793:Thallium; D045647:DNA Glycosylases; C479058:oxoguanine glycosylase 1, human