title: Combined use of Overhauser spectroscopy and NMR diffusion experiments for mapping the hydration structure of nucleosides: structure and dynamics of uridine in water.
abstract: Complementary results from 13C intermolecular nuclear Overhauser effects (NOE), 1H-13C heteronuclear Overhauser spectroscopy (HOSEY) and 1H-NMR diffusion measurements were used for probing the structure of the first solvation shell of uridine in water. It is demonstrated that a cyclic dihydrate is formed. The two water molecules produce two hydrogen bonds with the two oxygen atoms from the pyrimidine ring and accept only one hydrogen bond from the amide proton. The dihydrate has only a short lifetime as compared with the rotational correlation time of the free nucleoside. The chemical exchange constant of the amide proton with water is then estimated by diffusion experiments. The results are consistent with previous data obtained for uracil in water and provide interesting information about water accessibility in nucleic acid bases.
authors.affiliation: Jeune Equipe 2421 TRACES, Université de Provence, case 512, Centre St Jérôme, 13397 Marseille Cedex 20, France.
authors.forename: Hadj B
authors.initials: HB
authors.lastname: Seba
authors.forename: Pierre
authors.initials: P
authors.lastname: Thureau
authors.forename: Bernard
authors.initials: B
authors.lastname: Ancian
authors.forename: André
authors.initials: A
authors.lastname: Thévand
mesh_terms: D004058:Diffusion; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D009705:Nucleosides / Q000737:chemistry*; D014529:Uridine / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D009705:Nucleosides; D014867:Water; D014529:Uridine