title: Crystal structure and photochemical behavior in solution of the 3'-N-sulfamate analogue of thymidylyl(3'-5')thymidine.
abstract: The 3'-N-sulfamate analogue of thymidylyl(3'-5')thymidine (TnsoT, 1) exhibits a preference for a C3'-endo conformation in the solution and solid states. Its photochemical behavior in solution is compared to that of its natural counterpart, thymidylyl(3'-5')thymidine (TpT, 2), to get further insight into the significance of the C3'-endo conformation on the photoproduct formation at the single-stranded dinucleotide level. Irradiation at 254 nm of 1 led to the same type of photoproducts as observed with 2. However, 1 was significantly more photoreactive than 2, and accordingly, the initial rate of photoproduct formation was enhanced in accordance with its propensity to base stack compared to 2. The corresponding quantum yields were determined and showed that the enhancement factor (1 compared to 2) is moderate for the cyclobutane pyrimidine dimer (CPD) (1.26) and much higher for the (6-4) photoproduct (1.8). These data strongly suggest that the CPD and (6-4) photoproduct arise from distinct minor stacked conformations.
authors.affiliation: Institut de Chimie des Substances Naturelles, CNRS, 1 Avenue de la Terrasse, 91190 Gif sur Yvette, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Moriou
authors.forename: Martial
authors.initials: M
authors.lastname: Thomas
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Adeline
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Martin
authors.forename: Angèle
authors.initials: A
authors.lastname: Chiaroni
authors.forename: Sylvie
authors.initials: S
authors.lastname: Pochet
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Fourrey
authors.forename: Alain
authors.initials: A
authors.lastname: Favre
authors.forename: Pascale
authors.initials: P
authors.lastname: Clivio
mesh_terms: D002241:Carbohydrates / Q000737:chemistry; D018360:Crystallography, X-Ray; D015226:Dinucleoside Phosphates / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010777:Photochemistry; D012996:Solutions; D013451:Sulfonic Acids / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D015226:Dinucleoside Phosphates; D012996:Solutions; D013451:Sulfonic Acids; C017758:thymidylyl-(3'-5')-thymidine