title: Covalent modifications to 2'-deoxyguanosine by 4-oxo-2-nonenal, a novel product of lipid peroxidation.
abstract: Two major products (adducts A and B) from the reaction of 2-deoxyguanosine (dGuo) with 13-hydroperoxylinoleic acid were detected by liquid chromatography/mass spectrometry (LC/MS). Adducts A and B were also the major products formed enzymatically when dGuo was incubated in the presence of linoleic acid and lipoxygenase. The mass spectral fragmentation patterns of adducts A and B suggested that unique modifications to the nucleoside had been introduced. This resulted in the characterization of a novel bifunctional electrophile, 4-oxo-2-nonenal, as the principal breakdown product of linoleic acid hydroperoxide. In subsequent studies, adduct A was found to be a substituted ethano dGuo adduct that was a mixture of three isomers (A(1)-A(3)) that all decomposed to form adduct B. Adduct A(1) was the hemiacetal form of 3-(2-deoxy-beta-D-erythropentafuranosyl)-3,5,6, 7-tetrahydro-6-hydroxy-7-(heptane-2-one)-9H-imidazo[1, 2-alpha]purine-9-one. Adducts A(2) and A(3) were the diastereomers of the open chain ketone form. Adduct B was the substituted etheno dGuo adduct, 3-(2-deoxy-beta-D-erythropentafuranosyl)imidazo-7-(heptane-2 -one)-9-hydroxy[1,2-alpha]purine, the dehydration product of adducts A(1)-A(3). Identical covalent modifications to dGuo were observed when calf-thymus DNA was treated with 4-oxo-2-nonenal. These data illustrate the diversity of reactive electrophiles produced from the peroxidative decomposition of lipids and have implications in fully assessing the role of lipid peroxidation in mutagenesis and carcinogenesis.
authors.affiliation: Center for Cancer Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6160, USA.
authors.forename: D
authors.initials: D
authors.lastname: Rindgen
authors.forename: M
authors.initials: M
authors.lastname: Nakajima
authors.forename: S
authors.initials: S
authors.lastname: Wehrli
authors.forename: K
authors.initials: K
authors.lastname: Xu
authors.forename: I A
authors.initials: IA
authors.lastname: Blair
mesh_terms: D000447:Aldehydes / Q000737:chemistry* / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000187:drug effects; D018736:DNA Adducts / Q000737:chemistry*; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000737:chemistry*; D008041:Linoleic Acids / Q000737:chemistry / Q000494:pharmacology; D015227:Lipid Peroxidation; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry
chemical_list: C403894:4-oxo-2-nonenal; D000447:Aldehydes; D018736:DNA Adducts; D008041:Linoleic Acids; D004247:DNA; D003849:Deoxyguanosine; C032890:13-hydroperoxylinoleic acid