Macromolecule Structure and Dynamics
One of the most traditional uses of NMR has been in structure determination of proteins and nucleic acids. Characterization of a target protein in solution can provide important knowledge for further drug discovery, especially for flexible proteins that are hard to crystallize or in the early stages of structural biology/drug discovery when crystallization conditions or strong enough inhibitors have not been discovered.
Once this work as been invested, a lot of interesting work can be done, including high resolution binding studies of ligands, metal binding, hydration, residual dynamics in various time scales, pH titrations of different protein protons etc.
Once the assignment is known, structure determination of a protein can be achieved by the extraction of structural parameters like NOE contacts, backbone coupling constants and residual dipolar couplings.
For proteins, this typically requires the expression of 15N/13C isotope labelled protein in minimal media, for larger proteins (> ~30 kDa) also with partial och complete deuteration. The protein also has to be possible to concentrate up to a final concentration of approximately 0.5 mM or more in a buffer not containing more than a total of ~0.2 mM salt in a volume of 300 µl.