A novel DNA N-glycosylase activity of E. coli T4 endonuclease V that excises 4,6-diamino-5-formamidopyrimidine from DNA, a UV-radiation- and hydroxyl radical-induced product of adenine

Miral Dizdaroglu, Tomasz H. Zastawny, J. Russ Carmical, R. Stephen Lloyd

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

We report on a novel activity of T4 endonuclease V. This enzyme is well known to be specific for the excision of pyrimidine dimers from UV-irradiated DNA. In this work, we show that T4 endonuclease V excises 4,6-diamino-5-formamidopyrimidine from DNA. 4,6-Diamino-5-formamidopyrimidine is formed as a product of adenine in DNA upon action of hydroxyl radicals and upon W-irradiation. DNA substrates were prepared by UV-or γ-irradiation of DNA in aqueous solution. DNA substrates were incubated either with active T4 endonuclease V or with heat-inactivated T4 endonuclease V or without the enzyme. After incubation, DNA was precipitated and supernatant fractions were separated. Supernatant fractions after derivatization, and pellets after hydrolysis and derivatization were analyzed by gas chromatography/isotope-dilution mass spectrometry. The results provide evidence for the excision of 4,6-diamino-5-formamidopyrimidine by T4 endonuclease V from both γ-and UV-irradiated DNA. Kinetics of excision were also determined. Fifteen other pyrimidine- and purine-derived base lesions that were identified in DNA samples were not substrates for this enzyme. It was concluded that, in addition to its well known activity for pyrimidine photodimers, T4 endonuclease V possesses an N-glycosylase activity for a major UV-radiation- and hydroxyl radical-induced monomeric product in DNA.

Original languageEnglish (US)
Pages (from-to)1-8
Number of pages8
JournalMutation Research - DNA Repair
Volume362
Issue number1
DOIs
StatePublished - Jan 2 1996

Keywords

  • 4,6-Diamino-5-formamidopyrimidine
  • DNA repair
  • Hydroxyl radical
  • Mutagenesis
  • UV-radiation

ASJC Scopus subject areas

  • Molecular Biology
  • Toxicology
  • Genetics

Fingerprint Dive into the research topics of 'A novel DNA N-glycosylase activity of E. coli T4 endonuclease V that excises 4,6-diamino-5-formamidopyrimidine from DNA, a UV-radiation- and hydroxyl radical-induced product of adenine'. Together they form a unique fingerprint.

  • Cite this