NMR studies of the exocyclic 1,N sub 6 -ethenodeoxyadenosine adduct (. epsilon. dA) opposite deoxyguanosine in a DNA duplex. epsilon. dA(syn)ter dot dG(anti) pairing at the lesion site

Proton NMR studies are reported on the complementary d(C-A-T-G-G-G-T-A-C){center dot}d(G-T-A-C-{epsilon}A-C-A-T-G) nonanucleotide duplex (designated {epsilon}dA{center dot}dG 9-mer duplex), which contains the exocyclic adduct 1,N{sup 6}-ethenodeoxyadenosine positioned opposite deoxyguanosine in the...

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Bibliographic Details
Published in:Biochemistry (Easton) 1991-02, Vol.30:7
Main Authors: de los Santos, C., Kouchakdjian, M., Patel, D.J., Yarema, K., Basu, A., Essigmann, J.
Format: Article
Language:English
Subjects:
550201 - Biochemistry- Tracer Techniques
ADDUCTS
AROMATICS
AZAARENES
BASIC BIOLOGICAL SCIENCES
CARCINOGENESIS
DNA ADDUCTS
GUANOSINE
HETEROCYCLIC COMPOUNDS
MAGNETIC RESONANCE
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
OLIGONUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OVERHAUSER EFFECT
PATHOGENESIS
PURINES
RESONANCE
RIBOSIDES
STEREOCHEMISTRY
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Summary:Proton NMR studies are reported on the complementary d(C-A-T-G-G-G-T-A-C){center dot}d(G-T-A-C-{epsilon}A-C-A-T-G) nonanucleotide duplex (designated {epsilon}dA{center dot}dG 9-mer duplex), which contains the exocyclic adduct 1,N{sup 6}-ethenodeoxyadenosine positioned opposite deoxyguanosine in the center of the helix. The present study focuses on the alignment of dG5 and {epsilon}dA14 at the lesion site in the {epsilon}dA{center dot}dG 9-mer duplex at neutral pH. This alignment has been characterized by monitoring the NOEs originating from the NH1 proton of dG5 and the H2, H5, and H7/H8 protons of {epsilon}dA14 in the central d(G4-G5-G6){center dot}d(C13-{epsilon}A14-C15) trinucleotide segment of the {epsilon}dA{center dot}dG 9-mer duplex. These NOE patterns establish that {epsilon}dA14 adopts a syn glycosidic torsion angle that positions the exocyclic ring toward the major groove edge while all the other bases including dG5 adopt anti glycosidic torsion angles. In summary, the dG5(anti){center dot}{epsilon}dA14(syn) alignment is readily accommodated into the DNA helix without disruption of flanking dG4{center dot}dC15 and dG6{center dot}dC13 base pairs and may account for the incorporation of dG opposite {epsilon}dA during in vitro replication by DNA polymerase I.
ISSN:0006-2960
1520-4995
DOI:10.1021/bi00221a015