1 Department of Chemistry and Biochemistry, Concordia University , 7141 Sherbrooke Street West, Montréal, Québec, Canada H4B 1R6.
2 Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine , Nashville, Tennessee 37232-0146, United States.

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

Biochemistry. 2015 Dec 29;54(51):7449-56

Authors: O'Flaherty DK, Guengerich FP, Egli M, Wilds CJ

Abstract

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 ? (hPol ?) was explored in vitro. Steady-state kinetics and mass spectrometric analysis of products from nucleotide incorporation revealed that although hPol ? 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 ?, in comparison to the 5'-dG of IaCL DNA containing the phosphodiester group.

PMID: 26624500 [PubMed - indexed for MEDLINE]