1. Introduction 292. Landmarks in NMR of macromolecules 322.1 Protein structures and methods development 322.1.1 Sequential assignment method 322.1.2 Triple-resonance experiments 342.1.3 Structures of large proteins 362.2 Protein–nucleic acid complexes 372.3 RNA structures 382.4 Membrane-bound systems 393. NMR spectroscopy today 403.1 State-of-the-art structure determination 413.2 New methods 443.2.1 Residual dipolar couplings 443.2.2 Direct detection of hydrogen bonds 443.2.3 Spin labeling 453.2.4 Segmental labeling 463.3 Protein complexes 473.4 Mobility studies 503.5 Determination of time-dependent structures 523.6 Drug discovery 534. The future of NMR 544.1 The ease of structure determination 544.2 The ease of making recombinant protein 554.3 Post-translationally modified proteins 554.4 Approaches to large and/or membrane-bound proteins 564.5 NMR in structural genomics 564.6 Synergy of NMR and crystallography in protein structure determination 565. Conclusion 576. Acknowledgements 577. References 57Since the publication of the first complete solution structure of a protein in 1985 (Williamson
et al. 1985), tremendous technological advances have brought nuclear magnetic resonance
spectroscopy to the forefront of structural biology. Innovations in magnet design, electronics,
pulse sequences, data analysis, and computational methods have combined to make NMR an
extremely powerful technique for studying biological macromolecules at atomic resolution
(Clore & Gronenborn, 1998). Most recently, new labeling and pulse techniques have been
developed that push the fundamental line-width limit for resolution in NMR spectroscopy,
making it possible to obtain high-field spectra with better resolution than ever before (Dötsch
& Wagner, 1998). These methods are facilitating the study of systems of ever-increasing
complexity and molecular weight.
