Metabolic activation of chrysene by hamster embryo cells: evidence for the formation of a 'bay-region' diol-epoxide-N2-guanine adduct in RNA.

Ribonucleoside-hydrocarbon adducts present in hydrolysates of RNA isolated from hamster embryo cells treated with 3H-labelled chrysene were examined by chromatography on Sephadex LH20 and by h.p.l.c. on Zorbax ODS. Two adducts formed in cells had chromatographic properties identical to those of two synthetic adducts formed when r-1,t-2-dihydroxy-t-3,4-oxy-1,2,3,4-tetrahydrochrysene (antichrysene 1,2-diol 3,4-oxide) reacted with poly G in vitro. Another adduct formed in cells had chromatographic properties identical to those of a synthetic adduct formed when antichrysene 1,2-diol 3,4-oxide reacted with poly A. In addition to the characterized adducts, other minor adducts were detected whose structures are not known. The structure of the more abundant guanosine--hydrocarbon adduct formed in cells was investigated by determining its pK values and stability in 1 M KOH. The structures of the synthetic guanosine--hydrocarbon adducts were investigated by 1H-n.m.r. spectroscopy. The data show that, in the hydrocarbon--guanosine adducts studied, the hydrocarbon moiety is attached to the exocyclic amino group of guanine.