Fidelity and processivity of Saccharomyces cerevisiae DNA polymerase eta

J Biol Chem. 1999 Dec 24;274(52):36835-8. doi: 10.1074/jbc.274.52.36835.


The yeast RAD30 gene functions in error-free replication of UV-damaged DNA, and RAD30 encodes a DNA polymerase, pol eta, that has the ability to efficiently and correctly replicate past a cis-syn-thymine-thymine dimer in template DNA. To better understand the role of pol eta in damage bypass, we examined its fidelity and processivity on nondamaged DNA templates. Steady-state kinetic analyses of deoxynucleotide incorporation indicate that pol eta has a low fidelity, misincorporating deoxynucleotides with a frequency of about 10(-2) to 10(-3). Also pol eta has a low processivity, incorporating only a few nucleotides before dissociating. We suggest that pol eta's low fidelity reflects a flexibility in its active site rendering it more tolerant of DNA damage, while its low processivity limits its activity to reduce errors.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • DNA Damage
  • DNA Polymerase iota
  • DNA Replication
  • DNA-Directed DNA Polymerase / metabolism*
  • Kinetics
  • Mutation
  • Saccharomyces cerevisiae / enzymology*


  • DNA-Directed DNA Polymerase
  • Rad30 protein
  • DNA Polymerase iota