title: Far-UV photochemistry and photosensitization of 2'-deoxycytidylyl-(3'-5')-thymidine: isolation and characterization of the main photoproducts.
abstract: Far-UV irradiation of 2'-deoxycytidylyl-(3'-5')-thymidine (dCpT) gave rise to the pyrimidine (6-4) pyrimidone adduct and its Dewar valence isomer as the main photoproducts. The absolute configuration of the former adduct was determined and its photoisomerization studied. A comparison of the alkali lability of both compounds showed that hydrolysis of the phosphodiester bond occurs for the Dewar valence isomer but not for its (6-4) precursor. In addition, the trans-syn and cis-syn cyclobutane dimers of dCpT were obtained by acetophenone photosensitization and characterized. Finally, the deamination rate constants for this series of compounds were shown to be dramatically influenced by the nature and the configuration of the photoproducts.
authors.affiliation: Laboratoire des Lésions des Acides Nucléiques, DRFMC/SESAM, Centre d'Etudes Nucléaires de Grenoble, France.
authors.forename: T
authors.initials: T
authors.lastname: Douki
authors.forename: J
authors.initials: J
authors.lastname: Cadet
mesh_terms: D002942:Circular Dichroism; D004249:DNA Damage; D015226:Dinucleoside Phosphates / Q000737:chemistry / Q000528:radiation effects*; D008968:Molecular Conformation; D015394:Molecular Structure; D010782:Photolysis; D011740:Pyrimidine Dimers; D013329:Structure-Activity Relationship; D014466:Ultraviolet Rays
chemical_list: D015226:Dinucleoside Phosphates; D011740:Pyrimidine Dimers; C078504:2'-deoxycytidylyl-(3'-5')-thymidine