Conformational and topological analysis of the charge density in guanine-alpha-dicarbonyl adducts at AM1 level

The mutagenic activity molecular mechanism of the alpha-dicarbonyl compound s was related, by Rodriguez Mellado and coworkers, to the ability to form a dducts with the guanine residues of the nucleic acids. In this work, we hav e made a conformational, structural and topological study, from a theoretic al point of view, of the hydrogen bonding interactions in guanine-alpha-dic arbonyl adducts. The topological properties of the electronic charge density, based on the t heory of Atoms in Molecules and the semiempirical AM1 molecular orbital met hods, were calculated in the following adducts: G-glyoxal, I, G-methylglyox al, II, G-phenylglyoxal, G-diacetyl, and G-diphenylglyoxal. The results obt ained are compared with the available experimental data over mutagenicity o n Salmonella typhimurium strain TA100. (C) 2000 Elsevier Science B.V. All r ights reserved.