Reverse Micelle NMR

Though solution NMR has become a powerful tool for structural characterization of biological macromolecules, particularly proteins, it is fundamentally limited by the so-called ‘tumbling problem.’  Large proteins tumble relatively slowly in solution producing greatly broadened spectral lines as a result of fast transverse relaxation. Increased transverse relaxation not only broadens peaks but also decreases magnetization transfer efficiency, which drastically impedes collection of multi-dimensional data that is often needed for efficient analysis. Several strategies have been developed to mitigate these problems including the use of isotopic labeling schemes to minimize cross-relaxation and simplify spectra, the TROSY effect to reduce the detrimental effects of averaged transverse relaxation and the CRINEPT strategy for more optimal polarization transfer.  Unfortunately, limitations inherent to these approaches have restricted the precision of structural models for proteins of significant size.

Encapsulation of proteins within the protective aqueous of core of reverse micelles offers the ability to decrease macromolecular tumbling through preparation in low viscosity solvents such as liquid ethane. Gaining popularity, this novel sample also offers advantages in a variety of other contexts such as studies of integral and anchored membrane proteins, protein-ligand interactions, stabilization of the marginally stable proteins, protein hydration to name but a few applications.

RM synthesizer

Sample preparation is the key ingredient. Daedalus Innovations provides the only source of integrated sample preparation apparatus and high performance NMR sample tubes capable of seamless operation in modern cryogenic probes at the modest pressures necessary for reverse micelle NMR (generally less than 300 bar).

Liquid ethane is the ultra-low viscosity solvent of choice. The Daedalus Innovations reverse micelle sample synthesizer is the only commercially available apparatus designed specifically for the preparation of solutions of encapsulated proteins dissolved in low viscosity fluids. Designed to work with the X-treme 10 syringe pump and the high volume (3.6mm i.d.) ceramic high pressure NMR tube, the RM Synthesizer™ directs the creation of solutions of encapsulated proteins with ease.

 

Daedalus Innovations products are proudly designed, prototyped, and manufactured in the United States