Density Functional Study of Deoxycytidine Radicals In Irradiated DNA

Density functional theory is used to study the energetics and geometries of deoxycytidine radicals which are formed by removal of hydrogen from ve carbon atoms through irradiation. The C0 1 and C0 4 centered radicals (C0 1 and C0 4) are more energetically favored than the others. To investigate the cytosine release, a potential energy surface scan is performed to break the N1-glycosidic bond (N1-C0 1 bond). The result indicates that the activation energy needed for the N1-glycosidic bond breaking in every one of the deoxycytidine radicals is much lower than that in the parent deoxycytidine. The discussion shows that in irradiated molecular DNA, the C0 4 site is the most favored site for H abstraction; hence, there is C0 4-centered radical formation, subsequently leading to base release. This conclusion is in agreement with the experimental results. KCI Citation Count: 0