Mutagenic conformation of 8-oxo-7,8-dihydro-2′-dGTP in the confines of a DNA polymerase active site

The major product of oxidative base damage is 8-oxo-7,8-dihydro-2'-deoxyguanine (8odG). The coding potential of this lesion is modulated by its glycosidic torsion angle that controls whether its Watson-Crick or Hoogsteen edge is used for base pairing. The 2.0-angstrom structure of DNA polymerase (pol) beta bound with 8odGTP opposite template adenine indicates that the modified nucleotide assumes the mutagenic syn conformation and that the nonmutagenic anti conformation would be incompatible with efficient DNA synthesis.