Expanding the Scope of NMR Sample Preparation

NMRFAM aims to develop technologies specifically to simplify, to lower adoption barriers, and to accelerate utilization of state-of-the-art NMR techniques by a broader user community. NMRFAM works to determine how best to study particular samples by NMR and supports the development of new technologies to overcome the various hurdles and bottlenecks in each workflow. Thus, we facilitate studies by NMR of structure and dynamics in physiologically relevant preparations of samples.

The major aims of the TR&D1 are to develop and disseminate tools for the following stages of sample preparation:

Aim 1.  Sample preparation and transfer into SSNMR rotors

This aim prioritizes the development of rotor packing tools to enable quantitative transfer of a biological preparation into the rotor while maintaining its integrity of biological function (fully hydrated, at the desired pH, with additives dictated by the study requirements). NMRFAM is developing tools for a variety of rotor geometries, including 3.2, 2.5, 1.6 and 1.2 mm Varian/Agilent/Phoenix models as well as 3.2, 1.3 and 0.7 mm Bruker models, according to the priorities of NMRFAM user requests. We also have developed modifications to the packing devices to enable nearly quantitative transfer from one rotor type to another, to facilitate access to higher magnetic fields and spinning rates in smaller rotor geometries without requiring new samples.

Aim 2.  Transmembrane gradients under magic-angle spinning (MAS)

This aim enables MAS NMR experiments to be performed on membrane protein samples under well-defined conditions of chemistry, stoichiometry, lipid composition, pH, and electrical field among other environmental parameters. We are developing the tools and techniques to establish and maintain ion or voltage gradients, to utilize physiologic lipid compositions, to ensure membrane integrity while spinning, and to employ photoillumination strategies for creating proton motive forces and voltage gradients.

Aim 3.  Manipulation of sample conditions within the NMR rotor

This aim preserves, protects and defends the constitution of samples that have already been prepared and enables the manipulation of the sample conditions to titrate pH, ionic strength and/or composition, and small molecule concentration. We are developing and validating technologies for adjusting these chemical parameters while ensuring that the resulting NMR experiments accurately reflect the desired conditions. Furthermore, this effort enhances the sustainability of NMR, which is inherently a non-destructive technique, by ensuring that samples can be used for many different types of experiments required throughout a study without the need for preparing numerous expensive isotopically labeled samples.