8-OxodGTP Incorporation by DNA Polymerase β Is Modified by Active-Site Residue Asn279

Citations Over TimeTop 17% of 2000 papers

Abstract

To understand how the active site of a DNA polymerase might modulate the coding of 8-oxo-7,8-dihydrodeoxyguanine (8-oxodG), we performed steady-state kinetic analyses using wild-type DNA polymerase beta (pol beta) and two active-site mutants. We compared the coding of these polymerases by calculating the ratio of efficiencies for incorporation of dATP and dCTP opposite 8-oxodG and for incorporation of 8-oxodGTP opposite dA and dC. For wild-type pol beta, there is a 2:1 preference for incorporation of dCTP over dATP opposite 8-oxodG using a 5'-phosphorylated 4-base gap substrate. Mutation of either Asn279 or Arg283 to alanine has almost no effect on the ratio. 8-OxodGTP is preferentially incorporated opposite a template dA (24:1) by wild-type pol beta; mutation of Asn279 to alanine results dramatic change whereby there is preferential incorporation of 8-oxodGTP opposite dC (14:1). This suggests that interactions of 8-oxodGTP with Asn279 in the polymerase active site may alter the conformation of 8-oxodGTP and therefore alter its misincorporation.

Related Papers

• → A specific subdomain in φ29 DNA polymerase confers both processivity and strand-displacement capacity(2005)92 cited
• → A peptide switch regulates DNA polymerase processivity(2003)82 cited
• → DNA polymerase beta bypasses in vitro a single d(GpG)-cisplatin adduct placed on codon 13 of the HRAS gene.(1995)110 cited
• → Synthetic Activity of Sso DNA Polymerase Y1, an Archaeal DinB-like DNA Polymerase, Is Stimulated by Processivity Factors Proliferating Cell Nuclear Antigen and Replication Factor C(2001)56 cited
• → Mechanistic Insights into Replication Across from Bulky DNA Adducts: A Mutant Polymerase I Allows an N-Acetyl-2-aminofluorene Adduct To Be Accommodated during DNA Synthesis(2003)15 cited