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Title: Monomeric base damage products from adenine, guanine, and thymine induced by exposure of DNA to ultraviolet radiation

Abstract

The formation of monomeric products in DNA upon exposure to UV radiation was investigated. Three novel products were identified in DNA in aqueous solution upon exposure to UV radiation at 254 nm in a dose range from 100 to 10 000 J/m{sup 2}. These were 4,6-diamino-5-formamidopyrimidine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, and 5-hydroxy-5,6-dihydrothymine. These three products are known to be substrates for base excision repair enzymes involved in the reversal of oxidative DNA damage. The dependence of the yields of formamidopyrimidines on UV radiation dose was nonlinear, whereas the yield of 5-hydroxy-5,6-dihydrothymine was increased linearly in the entire dose range. Of these products, 4,6-diamino-5-formamidopyrimidine was the only compound produced in appreciable amounts at 310 nm. At the highest dose used, the formation of other pyrimidine- and purine-derived products was also observed. Their amounts, however, were increased above control levels up to 2-fold only. The hydroxyl radical scavenger dimethyl sulfoxide has no effect on product yields excluding the involvement of hydroxyl radical in product formation. 4,6-Diamino-5-formamidopyrimidine and 2,6-diamino-4-hydroxy-5-formamidopyrimidine may be produced by hydration of adenine and guanine, respectively, across the N(7)-C(8) double bond by mechanisms similar to those proposed previously for well-known formation of pyrimidine hydrates with the hydroxyl group located at C(6). Formation ofmore » 5-hydroxy-5,6-dihydrothymine indicates that hydration of thymine with the hydroxyl group located at C(5) of the pyrimidine ring also occurs. The results of these studies indicate that these monomeric base damage products could be a biologically important component of the photoproducts that are responsible for the deleterious effects of UV radiation. 50 refs., 5 figs.« less

Authors:
;  [1];  [2]
  1. Emory Univ. School of Medicine, Atlanta, GA (United States)
  2. National Institute of Standards and Technology, Gaithersburg, MD (United States); and others
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
415170
Resource Type:
Journal Article
Journal Name:
Biochemistry (Eaton)
Additional Journal Information:
Journal Volume: 34; Journal Issue: 3; Other Information: PBD: 24 Jan 1995
Country of Publication:
United States
Language:
English
Subject:
56 BIOLOGY AND MEDICINE, APPLIED STUDIES; DNA; BIOLOGICAL RADIATION EFFECTS; EXCISION REPAIR; GUANINE; HYDRATES; THYMINE; ULTRAVIOLET RADIATION; ENZYME ACTIVITY; DOSE-RESPONSE RELATIONSHIPS

Citation Formats

Doetsch, P W, Martin, A M, and Dizdarogly, M. Monomeric base damage products from adenine, guanine, and thymine induced by exposure of DNA to ultraviolet radiation. United States: N. p., 1995. Web. doi:10.1021/bi00003a005.
Doetsch, P W, Martin, A M, & Dizdarogly, M. Monomeric base damage products from adenine, guanine, and thymine induced by exposure of DNA to ultraviolet radiation. United States. https://doi.org/10.1021/bi00003a005
Doetsch, P W, Martin, A M, and Dizdarogly, M. 1995. "Monomeric base damage products from adenine, guanine, and thymine induced by exposure of DNA to ultraviolet radiation". United States. https://doi.org/10.1021/bi00003a005.
@article{osti_415170,
title = {Monomeric base damage products from adenine, guanine, and thymine induced by exposure of DNA to ultraviolet radiation},
author = {Doetsch, P W and Martin, A M and Dizdarogly, M},
abstractNote = {The formation of monomeric products in DNA upon exposure to UV radiation was investigated. Three novel products were identified in DNA in aqueous solution upon exposure to UV radiation at 254 nm in a dose range from 100 to 10 000 J/m{sup 2}. These were 4,6-diamino-5-formamidopyrimidine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, and 5-hydroxy-5,6-dihydrothymine. These three products are known to be substrates for base excision repair enzymes involved in the reversal of oxidative DNA damage. The dependence of the yields of formamidopyrimidines on UV radiation dose was nonlinear, whereas the yield of 5-hydroxy-5,6-dihydrothymine was increased linearly in the entire dose range. Of these products, 4,6-diamino-5-formamidopyrimidine was the only compound produced in appreciable amounts at 310 nm. At the highest dose used, the formation of other pyrimidine- and purine-derived products was also observed. Their amounts, however, were increased above control levels up to 2-fold only. The hydroxyl radical scavenger dimethyl sulfoxide has no effect on product yields excluding the involvement of hydroxyl radical in product formation. 4,6-Diamino-5-formamidopyrimidine and 2,6-diamino-4-hydroxy-5-formamidopyrimidine may be produced by hydration of adenine and guanine, respectively, across the N(7)-C(8) double bond by mechanisms similar to those proposed previously for well-known formation of pyrimidine hydrates with the hydroxyl group located at C(6). Formation of 5-hydroxy-5,6-dihydrothymine indicates that hydration of thymine with the hydroxyl group located at C(5) of the pyrimidine ring also occurs. The results of these studies indicate that these monomeric base damage products could be a biologically important component of the photoproducts that are responsible for the deleterious effects of UV radiation. 50 refs., 5 figs.},
doi = {10.1021/bi00003a005},
url = {https://www.osti.gov/biblio/415170}, journal = {Biochemistry (Eaton)},
number = 3,
volume = 34,
place = {United States},
year = {Tue Jan 24 00:00:00 EST 1995},
month = {Tue Jan 24 00:00:00 EST 1995}
}