DNA polymerase action blocked by adenine adducts induced by 5-hydroxymethylchrysene sulfate

Modification of M13mp10 single-stranded DNA with 5-hydroxymethylchrysene (5HCR) sulfate, the ultimate carcinogenic metabolite of 5-methylchrysene, resulted in formation of N6[(chrysen-5-yl)methyl]adenine and N2[(chrysen-5-yl)methyl]-guanine at the ratio of 2.7:1. Measurement of DNA synthesis using this modified template and E.coli DNA polymerase I (Klenow fragment) demonstrated that increasing levels of adducts caused a progressive decline in replication. Analysis of reaction products on DNA-sequence gels revealed DNA elongation to be arrested exclusively at adenine adducts in -AAAGGA- and -AACA- sequences.