Macromolecular Structure Determination: Comparison of X‐ray Crystallography and NMR Spectroscopy

Abstract

Abstract X‐ray crystallography and nuclear magnetic resonance (NMR) spectroscopy are the most powerful and predominant techniques used to experimentally determine the three‐dimensional structures of biological macromolecules at near atomic resolution. X‐ray diffraction (XRD) studies require a crystalisable protein, whereas NMR is suitable for macromolecules in solution. XRD has no size limitations and provides the most precise atomic detail, whereas information about the dynamics of the molecule may be limited. NMR excels in cases where no protein crystals can be obtained and it provides solution state dynamics, but in turn delivers lower resolution structures and is in general limited to molecular weights below approximately 50 kDa. The two techniques can deliver complementary information. Approximately 90% of the experimentally determined macromolecular structures deposited in Protein Data Bank are crystal structures, with NMR dominating the <10 kDa molecular weight range. Key Concepts: XRD and NMR are complimentary structure determination methods. XRD has no size limitations and provides the most precise atomic detail, whereas information about the dynamics of the molecule may be limited. NMR excels in cases where no protein crystals can be obtained and it provides solution state dynamics, but in turn delivers less detail and in general practice is limited to molecular weights below approximately 50 kDa.