title: Site-specific incorporation of nitroxide spin-labels into 2'-positions of nucleic acids.
abstract: A protocol is described for the incorporation of nitroxide spin-labels into specific 2'-sites within nucleic acids. This labeling strategy facilitates the investigation of nucleic acid structure and dynamics using electron paramagnetic resonance (EPR) spectroscopy and macromolecular complex formation using paramagnetic relaxation enhancement NMR spectroscopy. A spin-labeling reagent, 4-isocyanato TEMPO, which can be prepared in one facile step or obtained commercially, is used for postsynthetic modification of site-specifically 2'-amino-modified nucleic acids. This spin-labeling protocol has been applied primarily to RNA, but is also applicable to DNA. Subsequently, EPR spectroscopic analysis of the spin-labeled nucleic acids allows for the measurements of distances, solvent accessibilities and conformation dynamics. Using the spin-labeling strategy described here, spin-labeled samples can be prepared in 2-4 d.
authors: University of Iceland, Science Institute, Dunhaga 3, Reykjavik, Iceland.
authors: Thomas E
authors: TE
authors: Edwards
authors: Snorri Th
authors: ST
authors: Sigurdsson
mesh_terms: D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel; D019906:Nuclear Magnetic Resonance, Biomolecular; D016337:RNA, Catalytic / Q000737:chemistry*; D013113:Spin Labels
chemical_list: D003497:Cyclic N-Oxides; D016337:RNA, Catalytic; D013113:Spin Labels; C427204:hammerhead ribozyme; C003959:TEMPO