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Endonucleolytic incision of uvB irradiated DNA

Thesis/Dissertation ·
OSTI ID:6865474
Ultraviolet irradiation of DNA produces a variety of pyrimidine damages including pyrimidine dimers and 6-4' (pyrimidin-2' one)pyrimidines. Photoalkylation, the ultraviolet irradiation of DNA in the presence of isopropanol and a free radical photoinitiator had been shown to produce 8-(2-hydroxy-2-propyl)purines. An endonuclease activity against photoalkylated DNA was found in E. coli. This was assayed by conversion of photoalkylated superhelical PM2 phage DNA to the nicked form. Comparison of enzyme activities between crude extracts of E. coli strains demonstrated a deficiency associated with a mutant lacking endonuclease III. Irradiation of the DNA substrate in the absence of isopropanol did not affect the activity in any strain studied. Therefore, the substrate photoproduct for endonuclease III is not an 8-(2-hydroxy-2-propyl)purine.
Research Organization:
Temple Univ., Philadelphia, PA (USA)
OSTI ID:
6865474
Country of Publication:
United States
Language:
English