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Title: Viewing Human DNA Polymerase β Faithfully and Unfaithfully Bypass an Oxidative Lesion by Time-Dependent Crystallography

One common oxidative DNA lesion, 8-oxo-7,8-dihydro-2'-deoxyguanine (8-oxoG), is highly mutagenic in vivo due to its anti-conformation forming a Watson–Crick base pair with correct deoxycytidine 5'-triphosphate (dCTP) and its syn-conformation forming a Hoogsteen base pair with incorrect deoxyadenosine 5'-triphosphate (dATP). Here in this article, we utilized time-resolved X-ray crystallography to follow 8-oxoG bypass by human DNA polymerase β (hPolβ). In the 12 solved structures, both Watson–Crick (anti-8-oxoG:anti-dCTP) and Hoogsteen (syn-8-oxoG:anti-dATP) base pairing were clearly visible and were maintained throughout the chemical reaction. Additionally, a third Mg2+ appeared during the process of phosphodiester bond formation and was located between the reacting α- and β-phosphates of the dNTP, suggesting its role in stabilizing reaction intermediates. After phosphodiester bond formation, hPolβ reopened its conformation, pyrophosphate was released, and the newly incorporated primer 3'-terminal nucleotide stacked, rather than base paired, with 8-oxoG. These structures provide the first real-time pictures, to our knowledge, of how a polymerase correctly and incorrectly bypasses a DNA lesion.
Authors:
 [1] ;  [1] ;  [2] ;  [2]
  1. The Ohio State Univ., Columbus, OH (United States). Dept of Chemistry and Biochemistry
  2. The Ohio State Univ., Columbus, OH (United States). Dept of Chemistry and Biochemistry; The Ohio State Univ., Columbus, OH (United States). Biophysics Programs
Publication Date:
OSTI Identifier:
1186920
Grant/Contract Number:
AC02-06CH11357; MCB-0960961; ES009127; ES024585
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 137; Journal Issue: 15; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org:
National Institutes of Health (NIH); National Science Foundation (NSF); USDOE Office of Science (SC)
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY