Radiation Damage in DNA

When DNA is irradiated, the resulting anions are primarily C(—) and T(—) [49]. However, the adiabatic electron affinities A Ea are Pu Pyr. The abundance of the Pyr(—) could imply inaccurate values of the AEa or lower-energy excited states of A(—) and G(—) in DNA. The CURES-EC A Ea of G, at 1.5 eV, agrees with the experimental value, but an E a of 0.3 0.05 eV is obtained for the local minimum dipolar planar anion. The dipole moment of G is similar to that of C and thus the DBEA should be about the same, 0.25 eV. The E and the predicted DBEA are approximately the same. 

67% of the spin resides on G. The spin density on the cytosine in the GC keto(—) form is similar to the spin density of the isolated anion of cytosine in that it is distributed over the complete molecule. The spin density in the GC enol(—) form is different in that the spin density is localized on a few atoms. 

One of the most important conclusions of this chapter is that there remains much to be done to characterize the thermal electron reactions of even the nucleic acids 

Available at http //www.nobel.se/medicine/educational/poster/1998. 

Berthold, H. Giessner-Prettre, G. and Pullman, A. Theoret. Chem. Acta 1966, 5, 53. 

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Andreev S.G., Khvostunov I.K., Spitkovskii D.M., Talyzina T.A., Biophysical modeling of radiation damage in DNA and chromatin induced by radiation of varying quality, Radiat. Biol. Radioecol., 1997,37,533-538. 

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