Selective covalent binding of the active sulfate ester of the carcinogen 5-(hydroxymethyl)chrysene to the adenine residue of calf thymus DNA.
5-(Hydroxymethyl)chrysene (5-HCR) sulfate, an active metabolite of the carcinogen 5-HCR, bound significantly in a covalent manner to the purine bases of calf thymus DNA through its 5-methylene carbon with loss of a sulfate anion when incubated at pH 7.4 and 37 degrees C. From the DNA were isolated two purine base adducts by high-pressure liquid chromatography, and they were identified as N6-[(chrysen-5-yl)methyl]adenine and N2-[(chrysen-5-yl)methyl]guanine with the corresponding synthetic specimens. The purine base adducts, appearing in the ratio 1 to 27 for guanine to adenine in the chromatogram, accounted for about 60% of the total covalent binding of 5-HCR sulfate to the DNA. 5-HCR sulfate also reacted specifically with the exocyclic amino groups of the purine bases of 2'-deoxyadenosine 5'-phosphate and 2'-deoxyguanosine 5'-phosphate at much lower rates than did with those of calf thymus DNA. Denaturing the DNA by heating followed by rapid cooling, covalent binding of 5-HCR sulfate to it markedly decreased with the increasing ratio of N2-guanine to N6-adenine adducts (1:3.6). These results strongly suggest that secondary structure of DNA has an influence on the covalent binding of 5-HCR sulfate and that intercalation of the sulfate ester into DNA base pairs plays an important role in its preferential binding to N6 of the adenine residue of native DNA.
Okuda
H
H
Department of Hygienic Chemistry, Tokyo College of Pharmacy, Japan.
Nojima
H
H
Miwa
K
K
Watanabe
N
N
Watabe
T
T
D000225:Adenine / Q000031:analogs & derivatives / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D002273:Carcinogens / Q000378:metabolism*; D002417:Cattle; D002911:Chrysenes / Q000302:isolation & purification / Q000378:metabolism*; D004247:DNA / Q000302:isolation & purification / Q000378:metabolism*; D018736:DNA Adducts; D003838:Deoxyadenine Nucleotides / Q000378:metabolism; D003848:Deoxyguanine Nucleotides / Q000378:metabolism; D006147:Guanine / Q000031:analogs & derivatives / Q000302:isolation & purification; D009691:Nucleic Acid Denaturation; D013950:Thymus Gland / Q000378:metabolism
D002273:Carcinogens; D002911:Chrysenes; D018736:DNA Adducts; D003838:Deoxyadenine Nucleotides; D003848:Deoxyguanine Nucleotides; C056613:chrysene-DNA adduct; C071620:N(6)-((chrysen-5-yl)methyl)adenine; C071619:N(2)-((chrysen-5-yl)methyl)guanine; D006147:Guanine; C032670:5-hydroxymethylchrysene; C007257:2'-deoxyguanosine 5'-phosphate; D004247:DNA; D000225:Adenine