We report the observation of anisotropic longitudinal electronic relaxation in nitroxide radicals under typical dynamic nuclear polarization conditions. This anisotropy affects the efficiency of dynamic nuclear polarization at cryogenic temperatures of 4 K and high magnetic fields of 6.7 T. Under our experimental conditions, the electron paramagnetic resonance spectrum of nitroxides such as TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl) is only partly averaged by electronic spectral diffusion, so that the relaxation times T1e(omega) vary across the spectrum. We demonstrate how the anisotropy of T1e(omega) can be taken into account in simple DNP models.
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Anisotropic longitudinal electronic relaxation affects DNP at cryogenic temperatures #DNPNMR
From The DNP-NMR Blog:
Anisotropic longitudinal electronic relaxation affects DNP at cryogenic temperatures #DNPNMR
Anisotropic relaxation effects are well know and understood in EPR spectroscopy and have long served as measures to understand the motion (libration) of paramagnetic co-factors (quinones, nitroxide radicals etc.) in biological system. In this study the authors investigate the effect of anisotropic relaxation effects in DNP experiments.
To find more about anisotropic relaxation effects studied by EPR take a look at the work by Sergei Dzuba or the Eatons:
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11-13-2017 03:03 PM
Phenylazide Hybrid-Silica - Polarization Platform for Dynamic Nuclear Polarization at Cryogenic Temperatures #DNPNMR
From The DNP-NMR Blog:
Phenylazide Hybrid-Silica - Polarization Platform for Dynamic Nuclear Polarization at Cryogenic Temperatures #DNPNMR
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Grüning, W.R., et al., Phenylazide Hybrid-Silica - Polarization Platform for Dynamic Nuclear Polarization at Cryogenic Temperatures. Helvetica Chimica Acta, 2016: p. n/a-n/a.
http://dx.doi.org/10.1002/hlca.201600122
[NMR paper] Fast hydrogen exchange affects (15)N relaxation measurements in intrinsically disordered proteins.
Fast hydrogen exchange affects (15)N relaxation measurements in intrinsically disordered proteins.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--production.springer.de-OnlineResources-Logos-springerlink.gif Related Articles Fast hydrogen exchange affects (15)N relaxation measurements in intrinsically disordered proteins.
J Biomol NMR. 2013 Jan 12;
Authors: Kim S, Wu KP, Baum J
Abstract
Unprotected amide protons can undergo fast hydrogen exchange (HX) with protons from the solvent. Generally, NMR experiments using the out-and-back...
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02-03-2013 10:22 AM
13C relaxation experiments for aromatic side chains employing longitudinal- and transverse-relaxation optimized NMR spectroscopy
13C relaxation experiments for aromatic side chains employing longitudinal- and transverse-relaxation optimized NMR spectroscopy
Abstract Aromatic side chains are prevalent in protein binding sites, perform functional roles in enzymatic catalysis, and form an integral part of the hydrophobic core of proteins. Thus, it is of great interest to probe the conformational dynamics of aromatic side chains and its response to biologically relevant events. Indeed, measurements of 13C relaxation rates in aromatic moieties have a long history in biomolecular NMR, primarily in the context of...
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07-05-2012 04:13 AM
Nuclear spin relaxation in isotropic and anisotropic media
Nuclear spin relaxation in isotropic and anisotropic media
Publication year: 2010
Source:Progress in Nuclear Magnetic Resonance Spectroscopy, Volume 57, Issue 2</br>
Matthew P. Nicholas, Ertan Eryilmaz, Fabien Ferrage, David Cowburn, Ranajeet Ghose</br>
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03-09-2012 09:16 AM
[NMR paper] Longitudinal (1)H relaxation optimization in TROSY NMR spectroscopy.
Longitudinal (1)H relaxation optimization in TROSY NMR spectroscopy.
Related Articles Longitudinal (1)H relaxation optimization in TROSY NMR spectroscopy.
J Am Chem Soc. 2002 Oct 30;124(43):12898-902
Authors: Pervushin K, Vögeli B, Eletsky A
A general method to enhance the sensitivity of the multidimensional NMR experiments performed at high-polarizing magnetic field via the significant reduction of the longitudinal proton relaxation times is described. The method is based on the use of two vast pools of "thermal bath" 1H spins residing on...
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11-24-2010 08:58 PM
Nuclear Spin Relaxation in Isotropic and Anisotropic Media
Nuclear Spin Relaxation in Isotropic and Anisotropic Media
Publication year: 2010
Source: Progress in Nuclear Magnetic Resonance Spectroscopy, In Press, Accepted Manuscript, Available online 29 April 2010</br>
Matthew P., Nicholas , Ertan, Eryilmaz , Fabien, Ferrage , David, Cowburn , Ranajeet, Ghose</br>
We present a unified framework to describe nuclear spin relaxation in isotropic and anisotropic solutions for single-domain diffusers. All expressions, diffusion and net spin-relaxation theory are derived ab initio. Complete analytical expressions are provided wherever...
Anisotropic longitudinal electronic relaxation affects DNP at cryogenic temperatures #DNPNMR
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