title: Tautomerism in 8-Nitroguanosine Studied by NMR and Theoretical Calculations.
abstract: The guanine base in DNA, due to its low oxidation potential, is particularly sensitive to chemical modifications. A large number of guanine lesions have been characterized and studied in some detail due to their relationship with tissue inflammations. Nevertheless, one example of these lesions is the formation of 8-nitro-guanosine, but the NMR data of this compound was only partially interpreted. A comprehensive study of the two possible tautomeric forms, through a detailed characterization of this compound, has implications for its base pairing properties. The target compound was obtained through a synthetic sequence of five steps, where all intermediates were fully characterized using spectral data. The analysis of the two tautomers was then evaluated through NMR spectroscopy and theoretical calculations of the chemical shifts and NH coupling constants, which were also compared with the data from guanosine.
authors.affiliation: a Chemistry Institute, University of Campinas, UNICAMP , P.O. Box 6154, 13083-970 , Campinas , SP , Brazil.
authors.forename: Thaís M
authors.initials: TM
authors.lastname: Barbosa
authors.affiliation: a Chemistry Institute, University of Campinas, UNICAMP , P.O. Box 6154, 13083-970 , Campinas , SP , Brazil.
authors.forename: Roberto
authors.initials: R
authors.lastname: Rittner
authors.affiliation: b Department of Chemistry , University of Liverpool , P.O. Box 147, L69 3BX Liverpool , UK.
authors.forename: Katie
authors.initials: K
authors.lastname: Alexander
authors.affiliation: b Department of Chemistry , University of Liverpool , P.O. Box 147, L69 3BX Liverpool , UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Cosstick
authors.affiliation: b Department of Chemistry , University of Liverpool , P.O. Box 147, L69 3BX Liverpool , UK.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Abraham
mesh_terms: D004247:DNA / Q000737:chemistry; D006151:Guanosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D013058:Mass Spectrometry / Q000379:methods; D008962:Models, Theoretical; D009574:Nitro Compounds / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: C481144:8-nitroguanosine; D009574:Nitro Compounds; D006151:Guanosine; D004247:DNA
keywords: DNA lesions; NMR; nitroguanosine; theoretical calculations