Solution structures of the (-)-cis-anti-benzo[a]pyrenyl-N{sup 2}-dG adduct and stereoisomerically related DNA adduct duplexes

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:538957

Cosman, M; Patel, D J ^[1]; Hingerty, B E ^[2]

---

1. Memorial Sloan-Kettering Cancer Center, New York, NY (United States)
2. Oak Ridge National Lab., TN (United States); and others

A combined NMR/computational study of the (-)-cis-anti-[BP]dG*.dC duplex completes our analysis of the structures of all four isomeric adducts derived from the addition of (+)- and (-)-anti-benzo[a]pyrene diol epoxides (BPDE) to N2-dG in the same 11-mer DNA duplex. In the (+)- and (-)-cis-adducts, the pyrenyl residues are intercalated but the modified deoxyguanines are displaced into the minor and major grooves respectively (base-displaced intercalation model). In contrast, in the (+)- and (-)-trans-adducts, the pyrenyl residues are located in the minor groove, and are oriented toward the 5{prime} or the 3{prime} end of the modified strand, respectively. Our key finding is that chiral anti-BPDE stereoisomers give rise to N2-dG adducts with opposite 5{prime} or 3{prime} orientations of the pyrenyl residues relative to the modified dG (trans-adducts), or with opposite rotations of the pyrenyl ring system about the helix axis (cis-adducts).

• OSTI ID: 538957
• Report Number(s): CONF-960807--
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
BENZOPYRENE
BIOLOGICAL EFFECTS
DNA ADDUCTS
EPOXIDES
ISOMERS
MOLECULAR STRUCTURE
MUTAGENS
RESIDUES