Strategies for 1 H-Detected Dynamic Nuclear Polarization Magic-Angle Spinning NMR Spectroscopy.

Maria Concistré,Philip T F Williamson,Ilya Kuprov,Marina Carravetta,Subhradip Paul

doi:10.1002/chem.202003463

Maria Concistré, Philip T F Williamson + Show 3 more

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https://doi.org/10.1002/chem.202003463

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Abstract

Combining dynamic nuclear polarization with proton detection significantly enhances the sensitivity of magic‐angle spinning NMR spectroscopy. Herein, the feasibility of proton‐detected experiments with slow (10 kHz) magic angle spinning was demonstrated. The improvement in sensitivity permits the acquisition of indirectly detected 14N NMR spectra allowing biomolecular structures to be characterized without recourse to isotope labelling. This provides a new tool for the structural characterization of environmental and medical samples, in which isotope labelling is frequently intractable.

Highlights

Combining dynamic nuclear polarization with proton detection significantly enhances the sensitivity of magic-angle spinning NMR spectroscopy
Spinning.[4b]. Here we introduce an experiment that is a triple combination of dynamic nuclear polarization (DNP), slow magic-angle spinning (MAS), and homonuclear decoupling, and use it to characterize amyloid fibrils composed of b2-microglobulin—a fairly typical biological system where we found that the isotope enrichment was not required
We identified three key factors that made the implementation possible: a) attenuation of proton signals from the DNP matrix in a way that does not interfere with the DNP enhancement; b) elimination of the strong homonuclear dipolar interactions using homonuclear decoupling schemes; and c) transverse magnetisation management to minimise losses through paramagnetic relaxation and inhomogeneous broadening

Summary

Introduction

Combining dynamic nuclear polarization with proton detection significantly enhances the sensitivity of magic-angle spinning NMR spectroscopy. In the absence of any homonuclear decoupling the proton spectrum was distributed into a family of sidebands spread over ~ 80 kHz, as expected given the low spinning speed and the strong network of dipolar coupled protons at this temperature.

Results

Conclusion