Mispairing of a site specific major groove (2S,3S)-N6-(2,3,4-trihydroxybutyl)-2'-deoxyadenosyl DNA Adduct of butadiene diol epoxide with deoxyguanosine: formation of a dA(anti).dG(anti) pairing interaction.
The (2S,3S)-N6-(2,3,4-trihydroxybutyl)-2'-deoxyadenosyl (BDT) adduct arising from alkylation of adenine N6 by butadiene diol epoxide (BDE) was placed opposite a mismatched deoxyguanosine nucleotide in the complementary strand of the oligodeoxynucleotide 5'-d(CGGACXAGAAG)-3'.5'-d(CTTCTGGTCCG)-3'. This oligodeoxynucleotide contains codon 61 (underlined) of the human N-ras protooncogene. The BDT adduct was at the second position of codon 61, and this was named the ras61 S,S-BDT-(61,2) A.G adduct. NMR spectroscopy revealed the presence of two conformations of the adducted mismatched duplex. In the major conformation, the mismatched base pair X6.G17 was oriented in a "face-to-face" orientation, in which both the modified nucleotide X6 and its complement G17 were intrahelical and in the anti conformation about the glycosyl bond. Hydrogen bonding was suggested between X6 N1 and G17 N1H and between X6 N6H and G17 O6. The presence of the BDT moiety allowed formation of a stable A.G mismatch pair. The identity of the minor conformation could not be determined. If not repaired, the resulting mismatch pair would generate A-->C mutations, which have been associated with this adenine N6 BDT adduct [Carmical, J. R., Nechev, L. N., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2000) Env. Mol. Mutagen. 35, 48-56].
Scholdberg
Tandace A
TA
Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, USA.
Nechev
Lubomir V
LV
Merritt
W Keither
WK
Harris
Thomas M
TM
Harris
Constance M
CM
Lloyd
R Stephen
RS
Stone
Michael P
MP
D020137:Base Pair Mismatch; D002070:Butadienes / Q000737:chemistry*; D018736:DNA Adducts / Q000737:chemistry*; D003839:Deoxyadenosines / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry*; D006018:Glycols / Q000737:chemistry*; D006801:Humans; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis; D011072:Poly U; D011522:Protons
D002070:Butadienes; D018736:DNA Adducts; D003839:Deoxyadenosines; D004852:Epoxy Compounds; D006018:Glycols; D009838:Oligodeoxyribonucleotides; D011522:Protons; C033446:oligo(dA)-poly(rU); C080053:3,4-epoxybutane-1,2-diol; D011072:Poly U