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Title: Structural and Kinetic Analysis of Nucleoside Triphosphate Incorporation Opposite an Abasic Site by Human Translesion DNA Polymerase η

The most prevalent lesion in DNA is an abasic site resulting from glycolytic cleavage of a base. In a number of cellular studies, abasic sites preferentially code for dATP insertion (the “A rule”). In some cases frameshifts are also common. X-ray structures with abasic sites in oligonucleotides have been reported for several microbial and human DNA polymerases (pols), e.g. Dpo4, RB69, KlenTaq, yeast pol ι, human (h) pol ι, and human pol β. We reported previously that hpol η is a major pol involved in abasic site bypass (Choi, J.-Y., Lim, S., Kim, E. J., Jo, A., and Guengerich, F. P. (2010 J. Mol. Biol. 404, 34–44). hpol η inserted all four dNTPs in steady-state and pre-steady-state assays, preferentially inserting A and G. In LC-MS analysis of primer-template pairs, A and G were inserted but little C or T was inserted. Frameshifts were observed when an appropriate pyrimidine was positioned 5' to the abasic site in the template. In x-ray structures of hpol η with a non-hydrolyzable analog of dATP or dGTP opposite an abasic site, H-bonding was observed between the phosphate 5' to the abasic site and water H-bonded to N1 and N6 of A and N1 and O6more » of G nucleoside triphosphate analogs, offering an explanation for what appears to be a “purine rule.” A structure was also obtained for an A inserted and bonded in the primer opposite the abasic site, but it did not pair with a 5' T in the template. Finally, we conclude that hpol η, a major copying enzyme with abasic sites, follows a purine rule, which can also lead to frameshifts. The phenomenon can be explained with H-bonds.« less
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  1. Vanderbilt Univ., Nashville, TN (United States). School of Medicine. Center in Molecular Toxicology. Dept. of Biochemistry
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC02-06CH11357; R01 ES010375; P01 CA160032; P30 ES000267
Accepted Manuscript
Journal Name:
Journal of Biological Chemistry
Additional Journal Information:
Journal Volume: 290; Journal Issue: 13; Journal ID: ISSN 0021-9258
American Society for Biochemistry and Molecular Biology
Research Org:
Vanderbilt Univ., Nashville, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Inst. of Health (NIH) (United States)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; DNA Damage; DNA Polymerase; Enzyme Kinetics; Pre-steady-state Kinetics; X-ray Crystallography