Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9591695 | Journal of Molecular Structure: THEOCHEM | 2005 | 8 Pages |
Abstract
8-Oxoguanine (8OG) is a mutagenic oxidative product of guanine, which may serve as a mispairing lesion during DNA duplication. It can form syn-anti conformation with cytosine (C), thymine (T), adenine (A) and a syn-anti like base pair with guanine (G). Using the density functional theory (DFT) we calculated the base pairing energies of these species. The resulting energies are all approximately â10 kcal molâ1, which is â¼15 kcal molâ1 lower than for the classical Watson-Crick G-C base pair and the competing 8OG-C classical pair. According to this, 8OG syn-anti configuration is un-favored when it comes to base pairing but not impossible, explaining the lack of specificity of 8OG. Oxidation of 8OG-C and 8OG-A leads to a proton shift from 8OG+ to C and A, i.e. charge spin separation occurs. Furthermore, the oxidation event results in â¼20 kcal molâ1 increase in the H-bond strength, which is again lost when the proton is removed from the N1-nitrogen of 8OG. All of the investigated base pairs form planar structures, in respect to the nucleotides making up the pairs, except 8OG-C that forms a â¼30° angle.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Jóhannes Reynisson, Steen Steenken,