REACTION WITH DNA AND MUTAGENIC SPECIFICITY OF SYN-BENZO[G]CHRYSENE 11,12-DIHYDRODIOL 13,14-EPOXIDE

The spectroscopic characterization of purine deoxyribonucleoside adduc ts derived from the fjord-region syn-benzo[g] chrysene 11,12-dihydrodi ol 13,14-epoxide and the mutagenic specificity of the latter compound for the supF gene in the pSP189 shuttle vector are described. This dih ydrodiol epoxide preferentially forms adducts with deoxyadenosine resi dues in DNA and is preferentially opened trans in reactions with DNA o r with deoxyribonucleotides. In common with other fjord-region syn-dih ydrodiol epoxides, the most frequently observed mutational changes wer e A --> T and G --> T changes. This hydrocarbon dihydrodiol epoxide is structurally similar to syn-benzo[c] phenanthrene 3,4-dihydrodiol 1,2 -epoxide but has an additional benzene ring annelated distant from the reaction center. As anticipated, there were some common features in t he chemistry and mutagenicities of these two compounds, but there were also substantive differences which indicate factors of importance in controlling reactions of these kinds of compounds with DNA.