View from Nuclear Magnetic Resonance Spectroscopy

Nuclear magnetic resonance (NMR) spectroscopy is one of the three major approaches for determining the structures of biological macromolecules. Historically, NMR spectroscopy was number two after X-ray crystallography in the rate of depositions to the Protein Data Bank (PDB). However, electron cryomicroscopy (CryoEM) recently surpassed NMR in this regard. NMR frequently is used in conjunction with X-ray or CryoEM in structure determinations. NMR has advantages over the other structural approaches in studies of conformational dynamics and interconverting conformational states of proteins and nucleic acids in solution. NMR spectroscopy, itself, can be considered as collection of hybrid methods in that structure determinations rely on the results of several separate magnetic resonance experiments that measure connectivities of magnetic-resonance-active nuclei through covalent bonds or through space or determine relative orientations of magnetic dipoles. NMR results frequently are combined with data from smallangle X-ray scattering or chemical crosslinking in developing structural models. NMR spectroscopy and CryoEM are particularly synergistic in that neither requires crystallization.