A B3LYP Study on Repair of Guanyl and 8-Oxoguanyl Radical by Simultaneous Proton- and Electron-Transfer Reaction

作者：Yamamura Mami; Ichino Tomoya; Yoshioka Yasunori^*

来源：Bulletin of the Chemical Society of Japan, 2011, 84(2): 181-190.

DOI：10.1246/bcsj.20100211

The proton transfers in base pairs of guanine (G)/8-oxoguanine (8G), 8G(+center dot)-C, PhOH-G(-H)(center dot), PhOH-8G(-H)(center dot), and 8G-G(-H)(center dot), have been theoretically examined in the gas phase at the B3LYP level of theory. For the 8G(+center dot)-C base pair, the single proton transfer proceeds from N1(8G(+center dot)) to N3(C) with the activation energy of 2.2 kcal mol(-1). The repairs of G(-H)(center dot) and 8G(-H)(center dot) bases to G and 8G have been studied by reaction with phenol, and the repair of G(-H)(center dot) base has been also studied for the pair with the 8G base. These three reactions proceed under the PCET mechanism, in which the proton transfers through the sigma-path, while the electron transfers through the pi-path. For reactions with PhO center dot and G(-H)(center dot), 80 easily delivers a proton and electron to yield PhOH and G. It is expected that 80 functions to protect other bases and amino acids from oxidation.

• 出版日期2011-2-15