title: Structural and biochemical impact of C8-aryl-guanine adducts within the NarI recognition DNA sequence: influence of aryl ring size on targeted and semi-targeted mutagenicity.
abstract: Chemical mutagens with an aromatic ring system may be enzymatically transformed to afford aryl radical species that preferentially react at the C8-site of 2'-deoxyguanosine (dG). The resulting carbon-linked C8-aryl-dG adduct possesses altered biophysical and genetic coding properties compared to the precursor nucleoside. Described herein are structural and in vitro mutagenicity studies of a series of fluorescent C8-aryl-dG analogues that differ in aryl ring size and are representative of authentic DNA adducts. These structural mimics have been inserted into a hotspot sequence for frameshift mutations, namely, the reiterated G3-position of the NarI sequence within 12mer (NarI(12)) and 22mer (NarI(22)) oligonucleotides. In the NarI(12) duplexes, the C8-aryl-dG adducts display a preference for adopting an anti-conformation opposite C, despite the strong syn preference of the free nucleoside. Using the NarI(22) sequence as a template for DNA synthesis in vitro, mutagenicity of the C8-aryl-dG adducts was assayed with representative high-fidelity replicative versus lesion bypass Y-family DNA polymerases, namely, Escherichia coli pol I Klenow fragment exo(-) (Kf(-)) and Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4). Our experiments provide a basis for a model involving a two-base slippage and subsequent realignment process to relate the miscoding properties of C-linked C8-aryl-dG adducts with their chemical structures.
authors.affiliation: Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1.
authors.forename: Michael
authors.initials: M
authors.lastname: Sproviero
authors.affiliation: Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1.
authors.forename: Anne M R
authors.initials: AM
authors.lastname: Verwey
authors.affiliation: Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1.
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Rankin
authors.affiliation: Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1.
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Witham
authors.affiliation: Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1.
authors.forename: Dmitriy V
authors.initials: DV
authors.lastname: Soldatov
authors.affiliation: Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1 rmanderv@uoguelph.ca.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Manderville
authors.affiliation: Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zürich, 8032 Zürich, Switzerland Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini, Cairo 11562, Egypt.
authors.forename: Mostafa I
authors.initials: MI
authors.lastname: Fekry
authors.affiliation: Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zürich, 8032 Zürich, Switzerland rmanderv@uoguelph.ca.
authors.forename: Shana J
authors.initials: SJ
authors.lastname: Sturla
authors.affiliation: Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, AB, Canada, T1K 3M4.
authors.forename: Purshotam
authors.initials: P
authors.lastname: Sharma
authors.affiliation: Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1 Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zürich, 8032 Zürich, Switzerland Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini, Cairo 11562, Egypt Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, AB, Canada, T1K 3M4 rmanderv@uoguelph.ca.
authors.forename: Stacey D
authors.initials: SD
authors.lastname: Wetmore
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000096:biosynthesis; D018736:DNA Adducts / Q000737:chemistry*; D004256:DNA Polymerase I / Q000378:metabolism; D019951:DNA Polymerase beta / Q000378:metabolism; D003849:Deoxyguanosine / Q000737:chemistry; D015252:Deoxyribonucleases, Type II Site-Specific; D056004:Molecular Dynamics Simulation; D016296:Mutagenesis; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation
chemical_list: D018736:DNA Adducts; D004247:DNA; D004256:DNA Polymerase I; D019951:DNA Polymerase beta; D015252:Deoxyribonucleases, Type II Site-Specific; C046719:GGCGCC-specific type II deoxyribonucleases; D003849:Deoxyguanosine