Synthesis of DNA oligonucleotides containing site-specifically incorporated O6-[4-oxo-4-(3-pyridyl)butyl]guanine and their reaction with O6-alkylguanine-DNA alkyltransferase

Lijuan Wang, Thomas Spratt, Anthony Pegg, Lisa A. Peterson

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

DNA pyridyloxobutylation occurs during the metabolic activation of the tobacco-specific nitrosamines, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN). This pathway contributes significantly to the carcinogenic and mutagenic activity of these nitrosamines. In general, the chemical structure of pyridyloxobutyl adducts are not well understood. Recently, an AGT reactive pyridyloxobutyl adduct was identified as O6-[4- oxo-4(3-pyridyl)butyl]guanine (O6-pobG). To better understand the importance of this adduct to the biological activity of pyridyloxobutylating agents, we developed a method for site-specifically incorporating O6-pobG into DNA oligonucleotides. They were synthesized using the phosphoramidite of the precursor 2'-deoxy-O6-{3-[2-(3-pyridyl)-1,3-dithian-2-yl]propyl}guanosine. The dithiane group was oxidatively removed with N-chlorosuccinimide in a final postoligomerization reaction to generate the desired product. Human AGT with a polyhistidine tag was able to repair the O6-pobG-containing DNA oligonucleotide, generating unmodified oligonucleotide. These results are consistent with an alkyl group transfer mechanism for the repair of O6-pobG by AGT.

Original languageEnglish (US)
Pages (from-to)127-131
Number of pages5
JournalChemical research in toxicology
Volume12
Issue number2
DOIs
StatePublished - Feb 1999

All Science Journal Classification (ASJC) codes

  • Toxicology

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