Understanding polymerase fidelity is an important objective towards ascertaining the overall stability of an organism's genome. Saccharomyces cerevisiae DNA polymerase η (yPol η ), a Y-family DNA polymerase, is known to efficiently bypass DNA lesions (e.g., pyrimidine dimers) in vivo. Using pre-steady-state kinetic methods, we examined both full-length and a truncated version of yPol η which contains only the polymerase domain. In the absence of yPol η 's C-terminal residues 514–632, the DNA binding affinity was weakened by 2-fold and the base substitution fidelity dropped by 3-fold. Thus, the C-terminus of yPol η may interact with DNA and slightly alter the conformation of the polymerase domain during catalysis. In general, yPol η discriminated between a correct and incorrect nucleotide more during the incorporation step (50-fold on average) than the ground-state binding step (18-fold on average). Blunt-end additions of dATP or pyrene nucleotide 5′ -triphosphate revealed the importance of base stacking during the binding of incorrect incoming nucleotides.
Brown, J. A., Zhang, L., Sherrer, S. M., Taylor, J.-S., Burgers, P. M. J., & Suo, Z. (2010). Pre-Steady-State Kinetic Analysis of Truncated and Full-Length Saccharomyces cerevisiae DNA Polymerase Eta . Journal of Nucleic Acids, 2010, 1–11. https://doi.org/10.4061/2010/871939