Copper generated reactive oxygen leads to formation of lysine-DNA adducts

Morwena J. Solivio, Tim J. Joy, Larry Sallans, Edward J. Merino

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20 Scopus citations

Abstract

This work describes the addition of a lysine derivative to guanine base in a nucleoside, an oligonucleotide, and to a large DNA that occurs via oxidation by copper generated reactive oxygen species. Nucleophiles present during oxidation leads to the formation of adducts. In this work, 2'-deoxyguanosine is oxidized by copper generated reactive oxygen species in the presence of a lysine derivative, Nα-acetyl-lysine methyl ester. Under these conditions the guanidinohydantoin-lysine adduct is observed in a relative yield of 27% when compared to other guanine oxidation products. MS2 strongly supports that lysine is added to the 5-position during the formation of guanidinohydantoin-lysine. A fourteen-nucleotide DNA duplex was oxidized under similar conditions. Digestion showed formation of the same guanidinohydantoin-lysine nucleoside. The reaction was then examined on a 392-nucleotide DNA substrate. Oxidation in the presence of the lysine ester showed adduct formation as stops in a primer extension assay. Adducts predominately formed at a 5'-GGG at position 415. Six of the seven sites that showed reaction greater than 3-fold above background were guanine sites. We conclude from this study that copper can catalyze the formation of DNA-protein adducts and may form in cells with elevated copper and oxidative stress.

Original languageEnglish (US)
Pages (from-to)1000-1005
Number of pages6
JournalJournal of Inorganic Biochemistry
Volume104
Issue number9
DOIs
StatePublished - Sep 1 2010

Keywords

  • 8-oxo-7,8-dihydro-2'-deoxyguanosine
  • Copper
  • DNA oxidation
  • DNA-protein crosslink
  • Guanidinohydantoin
  • Reactive oxygen species

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