NMR methods for studying the structure and dynamics of RNA.

Proper functioning of RNAs requires the formation of complex three-dimensional structures combined with the ability to rapidly interconvert between multiple functional states. This review covers recent advances in isotope-labeling strategies and NMR experimental approaches that have promise for facilitating solution structure determinations and dynamics studies of biologically active RNAs. Improved methods for the production of isotopically labeled RNAs combined with new multidimensional heteronuclear NMR experiments make it possible to dramatically reduce spectral crowding and simplify resonance assignments for RNAs. Several novel applications of experiments that directly detect hydrogen-bonding interactions are discussed. These studies demonstrate how NMR spectroscopy can be used to distinguish between possible secondary structures and identify mechanisms of ligand binding in RNAs. A variety of recently developed methods for measuring base and sugar residual dipolar couplings are de