Metal-Induced Point Defects in DNA: Model and Mechanisms

The aim of this work was to study the role of H3O and transition-metal (TM) ions in keto-enol and amino-imino tit 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 TM were determined being in file range from 0.02 (for Mg2+) to 1 (for Cu2+) and from 0 kcal/M (for Cu+) to 2.3 kcal/M (for Mg2+), respectively. It Was Shown that (3')ACC(5') (5')TGG(3') site of DNA double helix, which corresponds to the only triplet (5')UGG(3') 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')UGG(3') 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')CGG(3') triplet of RNA that codes arginine.