Formation of cyclobutane thymine dimers photosensitized by pyridopsoralens: Quantitative and qualitative distribution within DNA

Journal Article · Tue Jul 23 04:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00243a007· OSTI ID:5045966

Moysan, A; Viari, A; Vigny, P ^[1]; Voituriez, L; Cadet, J ^[2]; Moustacchi, E; Sage, E ^[3]

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1. Section de Physique et Chimie et Univ. Paris VI (France)
2. Centre d'Etudes Nucleaires, Grenoble (France)
3. CNRS, Paris (France)

As after irradiation with 254-nm UV light, exposure of thymidine and three isomeric pyridopsoralen derivatives to UVA radiation, in the dry state, leads to the formation of the six diastereomers of cyclobutadithymidine as the predominant reaction. This unexpected photosensitized reaction, which also gives rise to both 5R* and 5S* diastereomers of 5,6-dihydro-5-({alpha}-thymidylyl)thymidine (or spore photoproduct), is selective since (2+2) dimerization of 2{prime}-deoxycytidine was not detected under the same experimental conditions. The cis-syn isomer of cyclobutadithymine was also found to be produced within isolated DNA following UVA irradiation in aqueous solutions containing 7-methylpyrido (3,4-c)psoralen. Quantitatively, this photoproduct represents about one-fifth of the overall yield of the furan-side pyridopsoralen (2+2) photocycloadducts the thymine. DNA sequencing methodology was used to demonstrate that pyridopsoralen-photosensitized DNA is a substrate for T4 endonuclease V and Escherichia coli photoreactivating enzyme, two enzymes acting specifically on cyclobutane pyrimidine dimers. The formation of cyclobutane thymine dimers concomitant to that of thymine-furocoumarin photoadducts and their eventual implication in the photobiological effects of the pyridopsoralens are discussed.

• OSTI ID: 5045966
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:29; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ADDUCTS
ALKANES
ALPHA DECAY RADIOISOTOPES
ANTICOAGULANTS
AQUEOUS SOLUTIONS
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BUTANE
CALIFORNIUM 252
CALIFORNIUM ISOTOPES
COUMARINS
CYCLOALKANES
DISPERSIONS
DNA
DNA ADDUCTS
DNA SEQUENCING
DNA-ASE
DRUGS
ELECTROMAGNETIC RADIATION
ENDONUCLEASES
ENZYMES
ESCHERICHIA COLI
ESTERASES
EVEN-EVEN NUCLEI
EXTREME ULTRAVIOLET RADIATION
HEAVY NUCLEI
HEMATOLOGIC AGENTS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROLASES
ISOTOPES
MASS SPECTRA
MICROORGANISMS
MIXTURES
MOLECULAR STRUCTURE
NUCLEI
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOSPHODIESTERASES
PSORALEN
PYRIMIDINE DIMERS
RADIATION EFFECTS
RADIATIONS
RADIOISOTOPES
SOLUTIONS
SPECTRA
SPONTANEOUS FISSION RADIOISOTOPES
STEREOCHEMISTRY
STRUCTURAL CHEMICAL ANALYSIS
ULTRAVIOLET RADIATION
YEARS LIVING RADIOISOTOPES