Abstract: DNA is constantly exposed to endogenous and exogenous oxidative stresses. Damaged DNA can cause mutations, which may increase the risk of developing cancer and other diseases. G:C-C:G transversions are caused by various oxidative stresses. 2,2,4-Triamino-5(2H)-oxazolone (Oz), guanidinohydantoin (Gh)/iminoallantoin (Ia) and spiro-imino-dihydantoin (Sp) are known products of oxidative guanine damage. These damaged bases can base pair with guanine and cause G:C-C:G transversions. In this study, the stabilization energies of these bases paired with guanine were calculated in vacuo and in water. The calculated stabilization energies of the Ia:G base pairs were similar to that of the native C:G base pair, and both bases pairs have three hydrogen bonds. By contrast, the calculated stabilization energies of Gh:G, which form two hydrogen bonds, were lower than the Ia:G base pairs, suggesting that the stabilization energy depends on the number of hydrogen bonds. In addition, the Sp:G base pairs were less stable than the Ia:G base pairs. Furthermore, calculations showed that the Oz:G base pairs were less stable than the Ia:G, Gh:G and Sp:G base pairs, even though experimental results showed that incorporation of guanine opposite Oz is more efficient than that opposite Gh/Ia and Sp.
Keywords: oxidative guanine damage; base pair; hydrogen bond; stabilization energy
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Suzuki, M.; Kino, K.; Morikawa, M.; Kobayashi, T.; Komori, R.; Miyazawa, H. Calculation of the Stabilization Energies of Oxidatively Damaged Guanine Base Pairs with Guanine. Molecules 2012, 17, 6705-6715.
Suzuki M, Kino K, Morikawa M, Kobayashi T, Komori R, Miyazawa H. Calculation of the Stabilization Energies of Oxidatively Damaged Guanine Base Pairs with Guanine. Molecules. 2012; 17(6):6705-6715.
Suzuki, Masayo; Kino, Katsuhito; Morikawa, Masayuki; Kobayashi, Takanobu; Komori, Rie; Miyazawa, Hiroshi. 2012. "Calculation of the Stabilization Energies of Oxidatively Damaged Guanine Base Pairs with Guanine." Molecules 17, no. 6: 6705-6715.