Welcome to the Biomolecular NMR Facility page!
The NMR Facility is dedicated to providing state-of-the-art NMR technology as well as exceptional NMR experties. Together with X-ray crystallography, NMR spectroscopy is one of the two leading technologies for the structure determination of biomacromolecules at atomic resolution. In addition, NMR provides unique and important molecular motional and interaction profiles containing pivotal information on protein function. The information is also critical in drug development. Some of the applications of NMR spectroscopy are listed below:
- Solution structure: The only method for atomic-resolution structure determination of biomacromolecules in aqueous solutions under near physiological conditions or membrane mimeric environments.
- Molecular dynamics: The most powerful technique for quantifying motional properties of biomacromolecules.\
- Protein folding: The most powerful tool for determining the residual structures of unfolded proteins and the structures of folding intermediates.\
- Ionization state: The most powerful tool for determining the chemical properties of functional groups in biomacromolecules, such as the ionization states of ionizable groups at the active sites of enzymes.
- Weak intermolecular interactions: Allowing weak functional interactions between macrobiomolecules (e.g., those with dissociation constants in the micromolar to millimolar range) to be studied, which is not possible with other technologies.
- Protein hydration: A powerful tool for the detection of interior water and its interaction with biomacromolecules.
- Hydrogen bonding: A unique technique for the DIRECT detection of hydrogen bonding interactions.
- Drug screening and design: Particularly useful for identifying drug leads and determining the conformations of the compounds bound to enzymes, receptors, and other proteins.
- Metabolite analysis: A very powerful technology for metabolite analysis.
- Chemical analysis: A matured technique for chemical identification and conformational analysis of chemicals whether synthetic or natural.
Equipment available at the NMR Facility:
- Bruker Ascend™ 600 MHz I Variable Temprature unit (-40 to 80°C)
- Bruker Ascend™ 800 MHz I Variable Temprature unit (0 to 80°C)
Although NMR facility is dedicated to all kinds of possible applications, biomolecular research is the major emphasis. Biomacromolecular solution NMR study is the most important focus. Listed below are some basic common requirements for sample preparation, in particular protein samples in solution biomolecular NMR experiments.
- Common Profile: 0.1-2.5 mM concentration, typically about 1 mM; stable at room temperature over weeks; 2H/13C/15N isotope labeling; mono-disperse; purity greater than 95%; neither paramagnetic impurities nor solid particles present; organic buffer components in perdeuterated forms; 10-50 µM DSS or TSP as inner reference; 90%-95%H2O:10%-5%D2O.
- Volume: 500-550 µL for regular 5 mm NMR tubes and 260-300 µL for Shigemi tubes; 2-30 mg of protein of 8-30 kDa molecular weight, typically about 10 mg.
- Stability: No precipitation in proper buffers; no degradation with removal of proteases or addition of protease inhibitors; no decomposition by bacteria with addition of 10-50 µM NaN3 or use of micro-filtration; no oxidation (SH-groups) through addition of DTT.
- Buffer: pH: neutral or slightly acidic; phosphate buffer preferred; away from protein pI value. Ionic strength: less than 500 mM for conventional probes and less than 100 mM for cryogenic probes.
- Overexpression: E. coli strains preferred; chemically defined media (e.g. M9 and modifications) with 13C isotope enriched glucose/glycerol and 15N isotope enriched NH4Cl/(NH4)2SO4 as sole carbon source and nitrogen source, respectively, for uniformly 13C/15N labeling; protein yield more than 5 mg/L preferred.