The NMR Facility at Mayo currently supports three main fields of NMR biomedical application: Study of the structure of biomacromolecules in solution by high field, high resolution NMR spectroscopy:

• At present, NMR spectroscopy is the only technique that can provide detailed solution structure of small proteins and polynucleotides.

• NMR spectroscopy of small laboratory animals (in vivo NMR) and cell cultures:

  Due to the noninvasive character of the main interactions, NMR is very suitable for in vivo studies. It provides information on the composition and concentration of metabolites in body fluids, cells, tissues, and organs. In vivo NMR spectra are very useful for monitoring subtle metabolic changes.

• NMR imaging of small laboratory animals:

  The NMR experiment, when performed in a magnetic field with a controlled gradient, provides spatial distribution of observed spins, i.e. the NMR image, rather than NMR spectrum. The NMR images give noninvasive pictures of cross-sections of biological objects. Combined with spectroscopy, NMR images give a detailed map of the physiological state of a studied model.

For example, we are currently investigating how the drug levamisole helps the drug 5-FU extend the life of some patients who have undergone surgery for colon cancer. For those studies, we use nuclear magnetic resonance spectroscopy and follow the behavior of the drugs in human colon cancers growing in mice. We are monitoring the nuclear magnetic resonance signal of phosphorous and fluorine nuclei in tumor xenografts in mice. Phosphorous is a natural part of living systems. Fluorine is a major component of the drug 5-FU. By phosphorous NMR, we follow the viability of tumor cells and by fluorine NMR, the concentration and metabolism of the added drug 5-FU. The results of these studies will help determine how the two drugs interact in the body and may eventually lead to further improvements in therapy.

Data achievable with resource’s methodologies

• Structural and conformational analysis of proteins, nucleic acids, carbohydrates, lipids, and other biomolecules.
• Structure-function studies of macromolecular assemblies.
• Non-invasive analysis of the biochemistry of intact cells, tissue, or organs.
• In vivo investigations of the biochemistry of rats or other small animals.
• NMR imaging of small objects; NMR microscopy.
• High resolution studies of organic solids and dense fluids.

Service personnel

Routine spectra can be obtained and analyzed by facility staff on a service basis. Staff members are available for consultation on experiment design and training in data acquisition and processing.

Wet laboratory

Users have limited access to the wet laboratory for sample preparation.

Sample preparation (for small molecules, peptides or DNA)

Users may submit samples in solid form and facility staff will prepare the sample with the appropriate solvents and concentration.

Protein samples

Users desirous of investigating proteins using NMR may submit a viable clone of the protein in an expression system along with a written protocol for overexpression and purification. The facility staff will overexpress, isotope label (if necessary), purify and prepare the protein sample.

Core and collaborative research

Strategies for assigning NMR spectra of proteins. Determination of three-dimensional structures of proteins and nucleic acids from NMR data. Use of stable isotopes in two-dimensional NMR studies of proteins. Computer-aided design of NMR experiments, post-acquisition processing of NMR data and semi-automated analysis of multi-dimensional NMR data from proteins.

New concept/capability

Applications of NMR to protein engineering and drug design; elucidation of enzyme mechanisms and protein-ligand interactions. Application of multi-dimensional NMR methodology to the study of cellular biochemistry. Extensive assignments in protein NMR spectra through a combination of stable-isotope labeling and multi-dimensional NMR analysis. Use of ¹³C labeling and NMR relaxation measurements to determine site-specific dynamics in biomolecules–correlation times and order parameters. Rapid acquisition of two-dimensional NMR data for studies of intact cells and tissue.

Additional features

• All probes have deuterium lock capability and variable temperature control.
• X-nucleus decouplers are available for DRX-300WB and DRX-500 spectrometers.
• Specialized instrumentation and software, developed in-house, is made available to users as rapidly as possible.
• All spectrometers can perform rotating frame experiments (e.g., ROESY and TOCSY or HOHAHA), inverse-detection (¹H{X}), at multidimensional experiments.
• Imaging accessories on the DRX-300 wide bore include modified room- temperature shim coils, waveform memories, linear amplifiers, gradient power supply, high resolution solid state NMR of powders, and high-resolution display.
• Solid state accessories on the DRX-300 wide bore include Magic Angle Sample Spinning, heteronuclear detection (¹⁵N to ³¹P) and automatic sample changer.
• All spectrometers and workstations are linked to a local area network within the facility; the local area network is connected to the campus computer network by Ethernet.
• Users can archive their data on CD ROMs.