Characterization of the photodimers from DNA

Weinblum, D.

doi:10.1016/s0006-291x(67)80111-6

Cited by 46 publications

(10 citation statements)

References 7 publications

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“…The compound was prepared by irradiating thymine in frozen aqueous solution. Recrystallization of the crude product from water gave a crystalline material which exhibits an IR spectrum identical in all respects to that reported in the literature (Weinblum & Johns, 1966;Weinblum, 1967).…”

Section: Methodssupporting

confidence: 70%

“…cis-syn-Thymine-Uracil Cyclobutane Photodimer (Thy-[]Ura(c,s), 5a). The compound was separated from a mixture of Thy[]Thy, Thy[]Ura, and Ura[]Ura obtained from the irradiation of an equimolar mixture of thymine and uracil in frozen aqueous solution by cation-exchange chromatography on a column of AG 50W-X8 (ammonium formate) according to the procedure of Weinblum (1967). The IR spectrum of this compound is identical with the one reported.…”

Section: Methodsmentioning

confidence: 88%

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Photochemistry of cytosine derivatives. 1. Photochemistry of thymidylyl-(3' →5')-deoxycytidine

Liu¹,

Yang²

1978

Biochemistry

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The photochemistry of thymidylyl-(3' leads to 5')- deoxycytidine (dTpdC) was studied as a model system of adjacent thymine and cytosine bases in DNA. Acetophenonesensitized irradiation causes the cytosine moiety in dTpdC to react with the thymine moiety intramolecularly. Three unstable photoproducts are formed initially which are converted into three isomeric dinucleoside phosphates of thymine-uracil cyclobutane photodimer in a ratio of 4.2:2.2:1. Under the same irradiation condition thymidylyl-(3' leads to 5')-thymidine (dTpdT) yields two products in a ratio of 6:1. The structures of these products are established by chemical and spectroscopic methods. The major product in these reactions has been identified as the stereoisomer which has the same anti,anti relationship between the pyrimidine rings and the deoxyribose group as in the parent dinucleoside phosphates. The efficiency of the intramolecular dimerization of dTpdC is about one-third that of dTpdT. The results suggest that the cytosine base in DNA may be converted to a uracil base via photodimerization with an adjacent pyrimidine base, hydrolysis, and photoreactivation.

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Section: Methodssupporting

confidence: 70%

Section: Methodsmentioning

confidence: 88%

Photochemistry of cytosine derivatives. 1. Photochemistry of thymidylyl-(3' →5')-deoxycytidine

Liu¹,

Yang²

1978

Biochemistry

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“…Ultraviolet irradiation of D N A causes intrastrand dimerization of adjacent pyrimidines (Setlow et al, 1965 and references cited therein). In particular the thymine residues dimerize very rapidly and in native D N A the predominant photoproduct has the cis-syn configuration (Weinblum and Johns, 1966;Blackburn and Davies, 1967;Weinblum, 1967;Camerman and Camerman, 1970). The cyclobutane type dimer is chemically very stable and deactivates the biological functions of the D N A in which it is incorporated.…”

Section: Introductionmentioning

confidence: 99%

CIDNP DETECTED FLASH PHOTOLYSIS OF cis–syn 1,3 DIMETHYLTHYMINE DIMER

Kemmink

Eker

Kaptein

1986

Photochem & Photobiology

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Abstract— Theanthraquinone–2‐sulfonate photo‐sensitized splitting of cis‐syn 1,3‐dimethylthymine dimer gives rise to large CIDNP effects in the reaction product 1,3‐dimethylthymine. The polarization originates from a radical ion pair formed by electron transfer from the dimer to the triplet state sensitizer. In a deoxygenated solution the sign of the polarization of theC–6 proton is reversed compared to the predicted one on account of the CIDNP sign rules. In an aerated solution the correct sign is observed. This can be accounted for by assuming reduction of the lifetime of the radical pair in the presence of oxygen. The time‐resolved photo‐CIDNP technique was used to study the time dependence of the 1,3‐dimethylthymine signal. To account for this time‐dependence a cation radical disproportionation reaction is proposed.

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“…1). It has been demonstrated that tsTD is not produced in duplex DNA (38), but it is, however, generated when a singlestranded region of DNA is exposed to UV light (39). Singlestranded regions exist in DNA at the sites of replication and transcription.…”

Section: Discussionmentioning

confidence: 99%

Cyclobutane thymine dimers in arasproto-oncogene hot spot activate the gene by point mutation

Kamiya

Murata

et al. 1993

Nucl Acids Res

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ras proto-oncogenes with a cyclobutane-type thymine photodimer (cis-syn or trans-syn isomer) were constructed by replacement of a portion of the gene with a chemically synthesized fragment. When the genes were transfected by the calcium phosphate method into mouse NIH3T3 cells, they induced focus-formation, indicating that both photoproducts were mutagenic in mammalian cells. Sequence analysis of the ras gene fragments derived from the transformed cells showed that the genes were activated by a point mutation. The mutations detected most frequently were 3'-T-->A for the cis-syn isomer and 5'-T-->A for the trans-syn isomer. In contrast, a different trend of mutations was observed when a primer on a DNA template with a cis-syn dimer was extended in vitro by either DNA polymerase beta or alpha.

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Characterization of the photodimers from DNA

Cited by 46 publications

References 7 publications

Photochemistry of cytosine derivatives. 1. Photochemistry of thymidylyl-(3' →5')-deoxycytidine

Photochemistry of cytosine derivatives. 1. Photochemistry of thymidylyl-(3' →5')-deoxycytidine

CIDNP DETECTED FLASH PHOTOLYSIS OF cis–syn 1,3 DIMETHYLTHYMINE DIMER

Cyclobutane thymine dimers in arasproto-oncogene hot spot activate the gene by point mutation

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