Aflatoxin B1 and DNA adducts. Proposed model for surface noncovalent and covalent complexes with N(7) of guanine. II.
An alternate model for surface noncovalent and surface covalent binding of aflatoxin B1 to N(7) of guanine in DNA is proposed. This model considers the out-of-plane motions of C(8) of aflatoxin B1 in those interactions. The covalent intercalated fit of aflatoxin B1 into DNA arises from steric adjustments made by DNA at the covalent intercalation site as well as local strain in the bond angles about N(7) of guanine and C(8) of aflatoxin B1. The bond angle about N(7) deviates modestly from the sp2 value toward the sp3 value. This study suggests that the surface covalent aflatoxin B1-DNA complex serves only a minor role in aflatoxin's precarcinogenic interaction with DNA and is a likely correctable error.
Taylor
E R
ER
Department of Chemistry, University of Southwestern Louisiana, Lafayette 70504-44370.
D016604:Aflatoxin B1 / Q000737:chemistry*; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry*; D018736:DNA Adducts; D006147:Guanine / Q000737:chemistry*; D008968:Molecular Conformation; D014961:X-Ray Diffraction
D018736:DNA Adducts; C072611:aflatoxin B1-DNA adduct; D006147:Guanine; D004247:DNA; D016604:Aflatoxin B1