title: Assignment of resonances in the Escherichia coli 5 S RNA fragment proton NMR spectrum using uniform nitrogen-15 enrichment.
abstract: The downfield proton NMR spectrum of aqueous uniformly nitrogen-15 enriched 5 S RNA fragment is presented. Selective nitrogen-15 decoupling difference proton spectroscopy revealed nitrogen-15 chemical shifts of fragment imino nitrogens. Nitrogen chemical shifts of nucleic acid guanine and uracil imino nitrogens have separate small ranges. Nitrogen-15 and proton chemical shift correlation by the heteronuclear decoupling permitted the identification of the base type of some previously unassigned imino proton resonances in the 5 S RNA fragment spectrum. Corresponding resonances in the natural isotopic abundance 5 S RNA fragment spectrum are assigned to base types by comparison with the enriched sample spectrum.
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D004926:Escherichia coli; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009587:Nitrogen Isotopes; D009690:Nucleic Acid Conformation; D012335:RNA, Ribosomal
chemical_list: D009587:Nitrogen Isotopes; D012335:RNA, Ribosomal