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Base sequence selectivity in the binding of (+)anti-Benzo(a)pyrene diol epoxide to oligodeoxyribonucleotide duplexes

Thesis/Dissertation ·
OSTI ID:7233845

The effect of nucleotide sequence on the binding of (+)anti-Benzo[a]pyrene [(+)anti-BPDE] to the exocyclic amino group of deoxyguanosine (dG) was investigated with duplexes formed from self-complementary oligodeoxyribonucleotides of defined sequence. The oligodeoxyribonucleotides had the same base composition but differed in the primary nucleotide sequence. A [sup 35]S-postlabeling assay was used to quantitate the total level of (+)anti-BPDE bound to the duplexes. When (+)anti-BPDE was reacted with the oligodeoxyribonucleotide duplexes, non-random binding was observed. The duplex d(ATACGCGTAT) reacted the most extensively with (+)anti-BPDE. When the quantity of (+)anti-BPDE bound to dG was examined, most of the deoxyoligomers with two consecutive dG's reacted more extensively with (+)anti-BPDE than those which did not have two consecutive dG's. A modification of the [sup 35]S-postlabeling assay was developed to quantitate the amount of (+)anti-BPDE bound to each specific dG. Preferred sites of binding of (+)anti-BPDE were found. A central dG surrounded on the 5[prime] and 3[prime] sides by dC reacted the most extensively. Binding to a central dG was preferred when a dG neighbor was present. Alternating pyrimidine-purine sequences enhanced binding of (+)anti-BPDE to a central dG. (+)anti-BPDE was reacted with deoxyoligomer duplexes which contained varying lengths of dG runs. A greater quantity of (+)anti-BPDE bound per dG in the deoxyoligomer duplex containing 5 consecutive dG's compared to the duplex with 4 consecutive dG's. No differences in binding of (+)anti-BPDE per dG were found between the duplex containing 5 consecutive dG's compared to the duplex with 3 consecutive dG's. Factors other than the primary sequence of nucleotides may be responsible for the binding of (+)anti-BPDE to runs of dG's. Base sequence has a major effect on the interaction of (+)anti-BPDE with oligodeoxyribonucleotide duplexes.

Research Organization:
Purdue Univ., Lafayette, IN (United States)
OSTI ID:
7233845
Country of Publication:
United States
Language:
English