Aflatoxin B1 (AFB1) is produced by Aspergillus flavus. Its oxidation product, AFB1 epoxide, alkylates DNA at N7-dG.  The N7-dG adduct rearranges to a N7-dG formamidopyrimidine (FAPY) derivative. The AFB1-FAPY lesion equilibrates between alpha and beta deoxyribose anomers, with the b anomer favored in duplex DNA, while the a anomer is favored in single strand DNA.  The b to a conversion in single stranded oligonucleotides containing 5'-AXC-3' and 5'-AXT-3' sequences occurs more rapidly than for the 5'-AXA-3' sequence. Changing dA to deazaA at the 3'-neighbor nucleotide does not affect the conversion rate. Moreover, single-stranded oligonucleotides containing the 5'-AXC-3' and 5'-AXT-3' (X=FAPY modified dG) sequences show more a anomer at equilibrium than does the 5'-AXA-3' sequence. These results suggest a role for DNA sequence in modulating the chemistry of the AFB1-FAPY lesion in DNA.   Supported by NIH grant R01 CA-55678 (M.P.S.).

Sequence-dependent chemistry of the aflatoxin B<sub>1</sub>?formamidopyrimidine (FAPY) adduct in DNA

244th National Meeting (2012)

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Sequence-dependent chemistry of the aflatoxin B1?formamidopyrimidine (FAPY) adduct in DNA

Sequence-dependent chemistry of the aflatoxin B₁?formamidopyrimidine (FAPY) adduct in DNA