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Science 19 May 1967:
Vol. 156. no. 3777, pp. 955 - 957
DOI: 10.1126/science.156.3777.955
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Articles

Ultraviolet Irradiation of DNA in vitro and in vivo Produces a Third Thymine-Derived Product

A. J. Varghese 1 and Shih Yi Wang 2

1 Department of Biochlemizistry, School of Hygiene and Plublic Health, Johns Hopkins University, Baltimore, Macrylanzd 21205
2 Departmlenit of Biochlemizistry, School of Hygiene and Plublic Health, Johns Hopkins University, Baltimore, Macrylanzd 21205

A new thymine-derived product was separated from DNA irradiated with utlraviolet light in vitro and in vivo. This compound was mistaken to be thymine homodiner (T=T) by other workers because it is chromatographically indistinguishable from T=T in most eluents. It has absorbancy maximums at 312, 312, and 300 millimicrons in neutral, pH 2, and pH 11 aqueous solutions, respectively. When it is irradiated in aqueous solution with wavelengths of 360 and 313 millimicrons its spectrum reverts to one similar to that of thymine. Therefore, at least three thymine-derived products can be detected in ultraviolet irradiated DNA, namely the homodimer, a material with absorbancy maximum at 312 millimicrons, and a "minor" product suggested by others to be a dimer of cytosine and thymine. In cells, the latter two are formed in aboult equal amounts. While these three products were shown to exist in the acid hydrolyzates of ultraviolet irradiated DNA, a material with absorbancy maximum at about 310 millimicrons was demonstrated to form in ultraviolet irradiated DNA without further treatment. The magnitude of this spectral increase varied directly with the incrcase in the adenine-thymine contents in the DNA as shlown by differential transmittance spectra of the irradiated Micrococcus lysodeikticus, calf thymus, Bacillus cereus, and Hemophilus influenzae DNA.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Effects of photoreactivation of cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts on ultraviolet mutagenesis in SOS-induced repair-deficient Escherichia coli.
M. Tanaka, S. Nakajima, M. Ihara, T. Matsunaga, O. Nikaido, and K. Yamamoto (2001)
Mutagenesis 16, 1-6
   Abstract »    Full Text »    PDF »
Crystal and Molecular Structure of a Thymine-Thymine Adduct.
I. L. Karle, S. Y. Wang, and A. J. Varghese (1969)
Science 164, 183-184
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Uracil Photoproducts from Uracil Irradiated in Ice.
M. N. Khattak and S. Y. Wang (1969)
Science 163, 1341-1342
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Thymine-Thymine Adduct as a Photoproduct of Thymine.
A. J. Varghese and S. Y. Wang (1968)
Science 160, 186-187
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