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Formation and stability of repairable pyrimidine photohydrates in DNA.
Biochemistry. 1990 Nov 20; 29(46):10455-60.B

Abstract

Ultraviolet irradiation of poly(dG-dC) and poly(dA-dU) in solution produces pyrimidine hydrates that are repaired by bacterial and mammalian DNA glycosylases [Boorstein et al. (1989) Biochemistry 28, 6164-6170]. Escherichia coli endonuclease III was used to quantitate the formation and stability of these hydrates in the double-stranded alternating copolymers poly(dG-dC) and poly(dA-dU). When poly(dG-dC) was irradiated with 100 kJ/m2 of 254-nm light at pH 8.0, 2.2% of the cytosine residues were converted to cytosine hydrate (6-hydroxy-5,6-dihydrocytosine) while 0.09% were converted to uracil hydrate (6-hydroxy-5,6-dihydrouracil). To measure the stability of these products, poly(dG-dC) was incubated in solution for up to 24 h after UV irradiation. Cytosine hydrate was stable at 4 degrees C and decayed at 25, 37, and 55 degrees C with half-lives of 75, 25, and 6 h. Uracil hydrate produced in irradiated poly(dA-dU) was stable at 4 degrees C and at 25 degrees C and decayed with a half-life of 6 h at 37 degrees C and less than 0.5 h at 55 degrees C. Uracil hydrate and uracil were also formed in irradiated poly(dG-dC). These experiments demonstrate that UV-induced cytosine hydrate may persist in DNA for prolonged time periods and also undergo deamination to uracil hydrate, which in turn undergoes dehydration to yield uracil. The formation and stability of these photoproducts in DNA may have promoted the evolutionary development of the repair enzyme endonuclease III and analogous DNA glycosylase/endonuclease activities of higher organisms, as well as the development of uracil-DNA glycosylase.

Authors+Show Affiliations

Department of Pathology, New York University Medical Center, New York 10016.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

2271656

Citation

Boorstein, R J., et al. "Formation and Stability of Repairable Pyrimidine Photohydrates in DNA." Biochemistry, vol. 29, no. 46, 1990, pp. 10455-60.
Boorstein RJ, Hilbert TP, Cunningham RP, et al. Formation and stability of repairable pyrimidine photohydrates in DNA. Biochemistry. 1990;29(46):10455-60.
Boorstein, R. J., Hilbert, T. P., Cunningham, R. P., & Teebor, G. W. (1990). Formation and stability of repairable pyrimidine photohydrates in DNA. Biochemistry, 29(46), 10455-60.
Boorstein RJ, et al. Formation and Stability of Repairable Pyrimidine Photohydrates in DNA. Biochemistry. 1990 Nov 20;29(46):10455-60. PubMed PMID: 2271656.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Formation and stability of repairable pyrimidine photohydrates in DNA. AU - Boorstein,R J, AU - Hilbert,T P, AU - Cunningham,R P, AU - Teebor,G W, PY - 1990/11/20/pubmed PY - 1990/11/20/medline PY - 1990/11/20/entrez SP - 10455 EP - 60 JF - Biochemistry JO - Biochemistry VL - 29 IS - 46 N2 - Ultraviolet irradiation of poly(dG-dC) and poly(dA-dU) in solution produces pyrimidine hydrates that are repaired by bacterial and mammalian DNA glycosylases [Boorstein et al. (1989) Biochemistry 28, 6164-6170]. Escherichia coli endonuclease III was used to quantitate the formation and stability of these hydrates in the double-stranded alternating copolymers poly(dG-dC) and poly(dA-dU). When poly(dG-dC) was irradiated with 100 kJ/m2 of 254-nm light at pH 8.0, 2.2% of the cytosine residues were converted to cytosine hydrate (6-hydroxy-5,6-dihydrocytosine) while 0.09% were converted to uracil hydrate (6-hydroxy-5,6-dihydrouracil). To measure the stability of these products, poly(dG-dC) was incubated in solution for up to 24 h after UV irradiation. Cytosine hydrate was stable at 4 degrees C and decayed at 25, 37, and 55 degrees C with half-lives of 75, 25, and 6 h. Uracil hydrate produced in irradiated poly(dA-dU) was stable at 4 degrees C and at 25 degrees C and decayed with a half-life of 6 h at 37 degrees C and less than 0.5 h at 55 degrees C. Uracil hydrate and uracil were also formed in irradiated poly(dG-dC). These experiments demonstrate that UV-induced cytosine hydrate may persist in DNA for prolonged time periods and also undergo deamination to uracil hydrate, which in turn undergoes dehydration to yield uracil. The formation and stability of these photoproducts in DNA may have promoted the evolutionary development of the repair enzyme endonuclease III and analogous DNA glycosylase/endonuclease activities of higher organisms, as well as the development of uracil-DNA glycosylase. SN - 0006-2960 UR - https://www.unboundmedicine.com/medline/citation/2271656/Formation_and_stability_of_repairable_pyrimidine_photohydrates_in_DNA_ DB - PRIME DP - Unbound Medicine ER -