title: Sugar conformational effects on the photochemistry of thymidylyl(3'-5')thymidine.
abstract: The synthesis and conformational analysis of 2'-O,5-dimethyluridylyl(3'-5')-2'-O,5-dimethyluridine (1a), the analogue of thymidylyl(3'-5')thymidine (TpT; 1b) in which a methoxy group replaces each 2'-alpha-hydrogen atom, are described. In comparison with TpT, such modification increases the population of the C3'-endo conformer of the sugar ring puckering at the 5'- and 3'-ends from 30 to 75% and from 37 to 66%, respectively. Photolyses of 1a and TpT at 254 nm are qualitatively comparable (the cis-syn cyclobutane pyrimidine dimer and the (6-4) photoproduct are formed), although it is significantly faster in the case of 1a. These results are explained by the increased propensity of the modified dinucleotide to adopt a base-stacked conformation geometry reminiscent of that for TpT.
authors.affiliation: Institut de Chimie des Substances Naturelles, CNRS, 1 Avenue de la Terrasse, 91190 Gif sur Yvette, France.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Ostrowski
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Maurizot
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Adeline
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Fourrey
authors.forename: Pascale
authors.initials: P
authors.lastname: Clivio
mesh_terms: D002236:Carbohydrate Conformation; D002942:Circular Dichroism; D003855:Deoxyribose / Q000737:chemistry*; D015226:Dinucleoside Phosphates / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010777:Photochemistry
chemical_list: D015226:Dinucleoside Phosphates; C017758:thymidylyl-(3'-5')-thymidine; D003855:Deoxyribose