title: DNA Polymerase ν Rapidly Bypasses O6-Methyl-dG but Not O6-[4-(3-Pyridyl)-4-oxobutyl-dG and O2-Alkyl-dTs.
abstract: 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent tobacco carcinogen that forms mutagenic DNA adducts including O6-methyl-2'-deoxyguanosine (O6-Me-dG), O6-[4-(3-pyridyl)-4-oxobut-1-yl]-dG (O6-POB-dG), O2-methylthymidine (O2-Me-dT), and O2-POB-dT. We evaluated the ability of human DNA polymerase ν to bypass this damage to evaluate the structural constraints on substrates for pol ν and to evaluate if there is kinetic evidence suggesting the in vivo activity of pol ν on tobacco-induced DNA damage. Presteady-state kinetic analysis has indicated that O6-Me-dG is a good substrate for pol ν, while O6-POB-dG and the O2-alkyl-dT adducts are poor substrates for pol ν. The reactivity with O6-Me-dG is high with a preference for dCTP > dGTP > dATP > dTTP. The catalytic activity of pol ν toward O6-Me-dG is high and can potentially be involved in its bypass in vivo. In contrast, pol ν is unlikely to bypass O6-POB-dG or the O2-alkyl-dTs in vivo.
authors.affiliation: Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Pennsylvania State University , Hershey, Pennsylvania 17033, United States.
authors.forename: A S Prakasha
authors.initials: AS
authors.lastname: Gowda
authors.affiliation: Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Pennsylvania State University , Hershey, Pennsylvania 17033, United States.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Spratt
mesh_terms: D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D007700:Kinetics; D013936:Thymidine / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; C015558:O(6)-methyl-2'-deoxyguanosine; C120926:DNA polymerase V, E coli; D004259:DNA-Directed DNA Polymerase; D003849:Deoxyguanosine; D013936:Thymidine