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Oxidative damage to DNA generates 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG). During DNA replication and repair synthesis, 8-oxodG can pair with cytosine or adenine. The ability to accurately replicate through this lesion depends on the DNA polymerase. We report the first structure of a polymerase with a promutagenic DNA lesion, 8-oxodG, in the confines of its active site. The modified guanine residue is in an anti conformation and forms Watson-Crick hydrogen bonds with an incoming dCTP. To accommodate the oxygen at C8, the 5'-phosphate backbone of the templating nucleotide flips 180 degrees. Thus, the flexibility of the template sugar-phosphate backbone near the polymerase active site is one parameter that influences the anti-syn equilibrium of 8-oxodG. Our results provide insights into the mechanisms employed by polymerases to select the complementary dNTP.

Structure of DNA polymerase beta with the mutagenic DNA lesion 8-oxodeoxyguanine reveals structural insights into its coding potential., Krahn JM, Beard WA, Miller H, Grollman AP, Wilson SH, Structure. 2003 Jan;11(1):121-7. PMID:12517346

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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Categories: DNA-directed DNA polymerase | Homo sapiens | Beard, W A. | Grollman, A P. | Krahn, J M. | Miller, H. | Wilson, S H. | Dna | Transferase