Loop II of DNA polymerase beta is important for discrimination during substrate binding

George C. Lin, Joachim Jaeger, Kristin A. Eckert, Joann B. Sweasy

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Loop II of DNA polymerase beta (pol β) consists of 14 amino acid residues and is highly flexible and solvent exposed. Previous research from our laboratory has shown that this loop is important for polymerase activity and fidelity. In the study presented here, we demonstrate that a shortened five amino acid residue loop compromises the fidelity of pol β. This five-residue loop, termed ENEYP, induces one base frameshift errors and A-C transversions within a specific sequence context. We demonstrate that ENEYP misincorporates dGTP opposite template A at higher efficiencies than wild-type pol β. The kinetic basis for misincorporation is a defect in discrimination of the correct from incorrect dNTP substrate at the level of ground-state binding. Our results are consistent with the idea that loop II of pol β functions to maintain accurate DNA synthesis by a direct or indirect influence on the nucleotide binding pocket.

Original languageEnglish (US)
Pages (from-to)182-189
Number of pages8
JournalDNA Repair
Issue number2
StatePublished - Feb 1 2009
Externally publishedYes


  • Base excision repair
  • DNA polymerase beta
  • DNA repair
  • Structure and function

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


Dive into the research topics of 'Loop II of DNA polymerase beta is important for discrimination during substrate binding'. Together they form a unique fingerprint.

Cite this