title: The use of modified and non-natural nucleotides provide unique insights into pro-mutagenic replication catalyzed by polymerase eta.
abstract: This report evaluates the pro-mutagenic behavior of 8-oxo-guanine (8-oxo-G) by quantifying the ability of high-fidelity and specialized DNA polymerases to incorporate natural and modified nucleotides opposite this lesion. Although high-fidelity DNA polymerases such as pol δ and the bacteriophage T4 DNA polymerase replicating 8-oxo-G in an error-prone manner, they display remarkably low efficiencies for TLS compared to normal DNA synthesis. In contrast, pol η shows a combination of high efficiency and low fidelity when replicating 8-oxo-G. These combined properties are consistent with a pro-mutagenic role for pol η when replicating this DNA lesion. Studies using modified nucleotide analogs show that pol η relies heavily on hydrogen-bonding interactions during translesion DNA synthesis. However, nucleobase modifications such as alkylation to the N2 position of guanine significantly increase error-prone synthesis catalyzed by pol η when replicating 8-oxo-G. Molecular modeling studies demonstrate the existence of a hydrophobic pocket in pol η that participates in the increased utilization of certain hydrophobic nucleotides. A model is proposed for enhanced pro-mutagenic replication catalyzed by pol η that couples efficient incorporation of damaged nucleotides opposite oxidized DNA lesions created by reactive oxygen species. The biological implications of this model toward increasing mutagenic events in lung cancer are discussed.
authors.affiliation: Department of Chemistry, Cleveland State University, 2351 Euclid Avenue, Cleveland, OH 44115, USA.
authors.forename: Jung-Suk
authors.initials: JS
authors.lastname: Choi
authors.affiliation: Department of Chemistry, Cleveland State University, 2351 Euclid Avenue, Cleveland, OH 44115, USA.
authors.forename: Anvesh
authors.initials: A
authors.lastname: Dasari
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 413 Wartik Building, University Park, PA 16802, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Hu
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 413 Wartik Building, University Park, PA 16802, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Benkovic
authors.affiliation: Department of Chemistry, Cleveland State University, 2351 Euclid Avenue, Cleveland, OH 44115, USA Center for Gene Regulation in Health and Disease, Cleveland State University, 2351 Euclid Avenue, Cleveland, OH 44115, USA Case Comprehensive Cancer Center, 10900 Euclid Avenue, Cleveland OH 44106, USA a.berdis@csuohio.edu.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Berdis
mesh_terms: D055162:Biocatalysis; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D009153:Mutagens / Q000633:toxicity*; D009690:Nucleic Acid Conformation; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism*; D000099270:Y-Family DNA Polymerases
chemical_list: D004259:DNA-Directed DNA Polymerase; D009153:Mutagens; D009711:Nucleotides; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases