Backbone Flexibility Influences Nucleotide Incorporation by Human Translesion DNA Polymerase η opposite Intrastrand Cross-Linked DNA.

O'Flaherty DK, Guengerich FP, Egli M, Wilds CJ
Biochemistry. 2015 54 (51): 7449-56

PMID: 26624500 · PMCID: PMC4889123 · DOI:10.1021/acs.biochem.5b01078

Intrastrand cross-links (IaCL) connecting two purine nucleobases in DNA pose a challenge to high-fidelity replication in the cell. Various repair pathways or polymerase bypass can cope with these lesions. The influence of the phosphodiester linkage between two neighboring 2'-deoxyguanosine (dG) residues attached through the O(6) atoms by an alkylene linker on bypass with human DNA polymerase η (hPol η) was explored in vitro. Steady-state kinetics and mass spectrometric analysis of products from nucleotide incorporation revealed that although hPol η is capable of bypassing the 3'-dG in a mostly error-free fashion, significant misinsertion was observed for the 5'-dG of the IaCL containing a butylene or heptylene linker. The lack of the phosphodiester linkage triggered an important increase in frameshift adduct formation across the 5'-dG by hPol η, in comparison to the 5'-dG of IaCL DNA containing the phosphodiester group.

MeSH Terms (7)

Chromatography, Liquid DNA DNA-Directed DNA Polymerase DNA Damage Humans Kinetics Tandem Mass Spectrometry

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