title: Metal-induced point defects in DNA: model and mechanisms.
abstract: The aim of this work was to study the role of H3O+ and transition-metal (TM) ions in keto-enol and amino-imino tautomeric transitions in DNA base pairs and depurination. In this regard, we discuss the thermodynamic model of ion-DNA interactions and UV display of double-proton transfer (DPT) in GC. The probabilities and energies of rare tautomeric forms of GC pairs in DNA induced by H3O+ and TMwere determined being in the range from0.02 (forMg2+) to 1 ( forCu2+), and from 0 kcal/m (for Cu2+) to 2.3 kcal/m (for Mg2+), respectively. It was shown that 3'ACC5'/5'TGG3' site of DNA double helix, which corresponds to the only triplet 5'UGG3' of RNA that codes the most valuable amino acid tryptophan, is a good target for TM ions to attack. It was also shown that the only way to obtain the tryptophan-coding 5'UGG3' triplet in RNA via transition-type G --> A point mutation caused by TM ions is their interaction with the site of a DNA double helix, which corresponds to 5'CGG3' triplet of RNA that codes arginine.
authors.affiliation: Andronikashvili Institute of Physics, 6 Tamarashvili Street, Tbilisi 0177, Georgia, (phone: +995-32-227233; fax: +995-32-391494).
authors.forename: Vasil G
authors.initials: VG
authors.lastname: Bregadze
authors.affiliation: Andronikashvili Institute of Physics, 6 Tamarashvili Street, Tbilisi 0177, Georgia, (phone: +995-32-227233; fax: +995-32-391494).
authors.forename: Eteri S
authors.initials: ES
authors.lastname: Gelagutashvili
authors.affiliation: Andronikashvili Institute of Physics, 6 Tamarashvili Street, Tbilisi 0177, Georgia, (phone: +995-32-227233; fax: +995-32-391494).
authors.forename: Ketevan J
authors.initials: KJ
authors.lastname: Tsakadze
authors.affiliation: Andronikashvili Institute of Physics, 6 Tamarashvili Street, Tbilisi 0177, Georgia, (phone: +995-32-227233; fax: +995-32-391494).
authors.forename: Sophia Z
authors.initials: SZ
authors.lastname: Melikishvili
mesh_terms: D020029:Base Pairing; D004247:DNA / Q000235:genetics*; D004249:DNA Damage; D006860:Hydrogen Bonding; D008024:Ligands; D019216:Metals, Heavy / Q000494:pharmacology*; D008957:Models, Genetic; D017354:Point Mutation; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D008024:Ligands; D019216:Metals, Heavy; D004247:DNA