Theoretical study on the multi-channel reaction of OH radical with 5-methylcytosine

All the addition and hydrogen abstraction reactions of OH radical with 5-methylcytosine (5-MeC) have been investigated by DFT methods. The results indicate that the preferred addition sites of OH radical to 5-MeC are at C5 and C6 and the H14 of methyl group abstraction reaction of 5-MeC by OH radical to produce P8 should be the dominant process. For the activation energies of OH radical addition to C5 and C6 cites of 5-MeC are very small, and the potential energy profiles along the reaction coordination is very flat around the transition structure.