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Mutation of the little finger domain in human DNA polymerase η alters fidelity when copying undamaged DNA
Author(s) -
Beardslee Renee A.,
Suarez Samuel C.,
Toffton Shan M.,
McCulloch Scott D.
Publication year - 2013
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.21807
Subject(s) - dna polymerase , pyrimidine dimer , dna clamp , polymerase , biology , dna replication , dna polymerase ii , dna , dna polymerase i , microbiology and biotechnology , dna polymerase delta , dna repair , biochemistry , genetics , polymerase chain reaction , gene , reverse transcriptase
DNA polymerase η (pol η) synthesizes past cyclobutane pyrimidine dimer and possibly 7,8‐dihydro‐8‐oxoguanine (8‐oxoG) lesions during DNA replication. Loss of pol η is associated with an increase in mutation rate, demonstrating its indispensable role in mutation suppression. It has been recently reported that β‐strand 12 (amino acids 316–324) of the little finger region correctly positions the template strand with the catalytic core of the enzyme. The authors hypothesized that modification of β‐strand 12 residues would disrupt correct enzyme–DNA alignment and alter pol η's activity and fidelity. To investigate this, the authors purified proteins containing the catalytic core of the polymerase, incorporated single amino acid changes to select β‐strand 12 residues, and evaluated DNA synthesis activity for each pol η. Lesion bypass efficiencies and replication fidelities when copying DNA‐containing cis‐syn cyclobutane thymine‐thymine dimer and 8‐oxoG lesions were determined and compared with the corresponding values for the wild‐type polymerase. The results confirm the importance of the β‐strand in polymerase function and show that fidelity is most often altered when undamaged DNA is copied. Additionally, it is shown that DNA–protein contacts distal to the active site can significantly affect the fidelity of synthesis. Environ. Mol. Mutagen. 54:638–651, 2013. © 2013 Wiley Periodicals, Inc.