The binding of polycyclic aromatic hydrocarbon diol-epoxides to DNA.

Diol-epoxide derivatives of polycyclic aromatic hydrocarbons are the ultimate carcinogenic forms of these compounds encountered in vivo. Using a novel electro-fluorescence apparatus, we report that, like the (+/-)-anti-diol-epoxide of benzo[a]pyrene (BP), the similar diol-epoxides of benzo[a]anthracene (BA) and 3-methylcholanthrene (3MC) also bind to the DNA helix at an inclination of approximately 50 degrees. This compares with the essentially perpendicular, intercalative-type binding generally found with saturated aromatic compounds, such as the native hydrocarbons, and may indicate a systematic behavior in the molecular associations precursive to carcinogenesis.