High-Temperature Dynamic Nuclear Polarization Enhanced Magic-Angle-Spinning NMR
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Dynamic nuclear polarization (DNP) transfers electron spin-polarization to nuclear spins in close proximity, increasing sensitivity by two-to-three orders of magnitude. This enables nuclear magnetic resonance (NMR) experiments on samples with low concentrations of analyte. The requirement of using cryogenic temperatures in DNP-enhanced solid-state NMR (ssNMR) experiments may impair the resolution and hence limit its broad application to biological systems. In this work, we introduce a “High-Temperature DNP” approach, which aims at increasing spectral resolution by performing experiments at temperatures of around 180 K instead of ~100 K. By utilizing the extraordinary enhancements obtained on deuterated proteins, still sufficiently large DNP enhancements of 11–18 are obtained for proton and carbon, respectively. We recorded high sensitivity 2D 13C–13C spectra in ~9 min with higher resolution than at 100 K, which has similar resolution to the one obtained at room temperature for some favorable residues.
KeywordsNuclear Magnetic Resonance Dynamic Nuclear Polarization Room Temperature Spectrum Dynamic Nuclear Polarization Enhancement Deuterated Sample
We acknowledge Sascha Lange, Trent W. Franks and Barth-Jan van Rossum for helpful discussions. Anne Diehl and Kristina Rehbein are also acknowledged for the preparation of the SH3 samples. This work was funded by the Deutsche Forschungsgemeinschaft (grant 05106/12-1 of the DIP program) and the European Union Seventh Framework programs (FP7/2007-2013) under the grant agreements 261863 (Bio-NMR).
- 21.S. Lange, A.H. Linden, U. Akbey, W. Trent Franks, N.M. Loening, B.J.v. Rossum, H. Oschkinat. J. Magn. Reson. 216, 209–212 (2012)Google Scholar