Collect. Czech. Chem. Commun. 1983, 48, 3517-3526

Semiempirical calculations of alkylation and protonation energies of bases of nucleic acids

Stanislav Miertuša and Magdaléna Trebatickáb

a Department of Analytical Chemistry, Slovak Institute of Technology, 812 37 Bratislava
b Institute of Physics and Biophysics, Comenius University, 842 15 Bratislava


The semiempirical quantum-chemical MINDO/3 method has been used to study protonation and alkylation of bases of nucleic acids: cytosine, thymine, uracil, adenine, and guanine. The optimum sites of attack of the reagents H(+), CH3(+), and C2H5(+) have been found among selected nucleophilic positions of the mentioned bases. At the same time interaction energies of protonation and alkylation have been expressed, and relative affinity of the considered positions to the protonation and alkylation has been evaluated.