MODELING OF AUGER-INDUCED DNA-DAMAGE BY INCORPORATED I-125

We have analyzed a newly available high resolution and precision repea t of the original Martin and Haseltine experiment which includes the i nfluence of DMSO on the results. The new model includes the production and diffusion of radical species and (OH)-O-. radical attack on DNA a s well as the direct hits. Calculations of single-strand breaks use in dividual Auger electron along with the tracks of electrons and radical species superimposed on an atomistic model of B-DNA. Comparison of th e preliminary calculations with the experiment supports the earlier ch oice of data for the amount of energy required to produce a single-str and break, i.e. 17.5 eV. In a separate simulation we found that an ave rage of less than two ionizations inducing a single-strand break gave the best fit to experimental data. Direct hits were found to be predom inantly occurring at short range while the damage by (OH)-O-. radicals was mainly of the long-range type.