Nov 20, 2019

Improved Structural Elucidation of Synthetic Polymers by Dynamic Nuclear Polarization Solid-State NMR Spectroscopy #DNPNMR

Ouari, Olivier, Trang Phan, Fabio Ziarelli, Gilles Casano, Fabien Aussenac, Pierre Thureau, Didier Gigmes, Paul Tordo, and Stéphane Viel. “Improved Structural Elucidation of Synthetic Polymers by Dynamic Nuclear Polarization Solid-State NMR Spectroscopy.” ACS Macro Letters 2, no. 8 (August 20, 2013): 715–19.

Dynamic nuclear polarization (DNP) is shown to greatly improve the solid-state nuclear magnetic resonance (SSNMR) analysis of synthetic polymers by allowing structural assignment of intrinsically diluted NMR signals, which are typically not detected in conventional SSNMR. Specifically, SSNMR and DNP SSNMR were comparatively used to study functional polymers for which precise structural elucidation of chain ends is essential to control their reactivity and to eventually obtain advanced polymeric materials of complex architecture. Results show that the polymer chain-end signals, while hardly observable in conventional SSNMR, could be clearly identified in the DNP SSNMR spectrum owing to the increase in sensitivity afforded by the DNP setup (a factor ∼10 was achieved here), hence providing access to detailed structural characterization within realistic experimental times. This sizable gain in sensitivity opens new avenues for the characterization of “smart” functional polymeric materials and new analytical perspectives in polymer science.

Nov 18, 2019

Large volume liquid state scalar Overhauser dynamic nuclear polarization at high magnetic field #DNPNMR

Dubroca, Thierry, Sungsool Wi, Johan van Tol, Lucio Frydman, and Stephen Hill. “Large Volume Liquid State Scalar Overhauser Dynamic Nuclear Polarization at High Magnetic Field.” Physical Chemistry Chemical Physics 21, no. 38 (2019): 21200–204.

Dynamic Nuclear Polarization (DNP) can increase the sensitivity of Nuclear Magnetic Resonance (NMR), but it is challenging in the liquid state at high magnetic fields. In this study we demonstrate significant enhancements of NMR signals (up to 70 on 13C) in the liquid state by scalar Overhauser DNP at 14.1 T, with high resolution (∼0.1 ppm) and relatively large sample volume (∼100 μL).

Nov 15, 2019

Modular, triple-resonance, transmission line DNP MAS probe for 500 MHz/330 GHz #DNPNMR

Reese, Marcel, Christy George, Chen Yang, Sudheer Jawla, J. Tassilo Grün, Harald Schwalbe, Christina Redfield, Richard J. Temkin, and Robert G. Griffin. “Modular, Triple-Resonance, Transmission Line DNP MAS Probe for 500 MHz/330 GHz.” Journal of Magnetic Resonance 307 (October 2019): 106573.

We describe the design and construction of a modular, triple-resonance, fully balanced, DNP-MAS probe based on transmission line technology and its integration into a 500MHz/330GHz DNP-NMR spectrometer. A novel quantitative probe design and characterization strategy is developed and employed to achieve optimal sensitivity, RF homogeneity and excellent isolation between channels. The resulting three channel HCN probe has a modular design with each individual, swappable module being equipped with connectorized, transmission line ports. This strategy permits attachment of a mating connector that facilitates accurate impedance measurements at these ports and allows characterization and adjustment (e.g. for balancing or tuning/matching) of each component individually. The RF performance of the probe is excellent; for example, the 13C channel attains a Rabi frequency of 280 kHz for a 3.2 mm rotor. In addition, a frequency tunable 330 GHz gyrotron operating at the second harmonic of the electron cyclotron frequency was developed for DNP applications. Careful alignment of the corrugated waveguide led to minimal loss of the microwave power, and an enhancement factor =180 was achieved for U-13C urea in the glassy matrix at 80 K. We demonstrated the operation of the system with acquisition of multidimensional spectra of cross-linked lysozyme crystals which are insoluble in glycerol-water mixtures used for DNP and samples of RNA.

Nov 14, 2019

[NMR] Postdoc: Solid-state NMR at 1.2 GHz

Postdoc position at ETH Zurich: for the development of fast MAS methods and biomolecular applications at high field (in particular at 1.2 GHz) in the group of Beat Meier (, we look for a postdoctoral researcher with a strong experimental background in solid-state NMR. Experience with NMR hardware and with biomolecular applications and structural biology is an asset. Spectrometers at 600 and 850 MHz are available and a 1.2 GHz system is expected in the first half of 2020.
The position is available from January 1, 2020 (or later) and is initially planned for for 1 year (renewable). Candidates should send a CV and the names of at least two references to Beat Meier (

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Postdoctoral position: DNP-enhanced biomolecular solid-state NMR-spectroscopy for the study of protein (mis)folding #DNPNMR

A postdoctoral position is available in the group of Henrike Heise at Forschungszentrum Juelich/Heinrich Heine University Duesseldorf

The successful candidate will study disordered and aggregation-prone proteins in all stages of the misfolding pathway. Further, interaction with potential drug candidates will be elucidated. State-of-the art solid-state NMR-spectroscopy, involvng polarization enhancement by DNP and fast magic angle spinning will be applied to elucidate those processes at atomic resolution. A selection of relevant publication is given below.

Our laboratory at the Forschungszentrum Jülich is equipped with state of the art solid-state NMR spectrometers operating at 800 and 600 MHz, DNP equipment is available for 600 and 800 MHz spectrometers. An ultrafast MAS probe head for spinning speeds up to > 100 kHz will be available soon, the installation of an ultrahigh field spectrometer operating at 1.2 GHz is scheduled for 2020.

The Forschungszentrum Jülich offers a vibrant research environment with close collaborations with the University of Düsseldorf, the RWTH Aachen University and the Max-Planck Institute Mülheim. Our laboratory is part of the Jülich center of structural biology JuStruct which bundles expertise with infrastructure in the field of atomic resolution of structural biology (NMR in solution and the solid state, X-ray crystallography,cryo-EM, molecular modelling and neutron scattering).

The initial appointment is for a year, with a possibility of renewal.The initial appointment is for a year, with a possibility of renewal.

Applications will be reviewed on a rolling basis, and candidates will be considered until the position is filled.

The ideal candidate should have a strong background in biomolecular NMR-spectroscopy. Experience with hyperpolarization and/ or Protein expression and purfication is a plus. Applicants must submit a cover letter summarizing research experience and specifying the interests in this position; a curriculum vitae (including a publication list); a statement of research interests; and two letters of reference to

Information about our group:

Selection of relevant publications:
  • L. Siemons, B. Uluca-Yazgi, R. B. Pritchard, S. McCarthy, H. Heise, D. F. Hansen, Determining isoleucine side-chain rotamer-sampling in proteins from 13C chemical shift, Chem.Commun. 2019, in press. doi:10.1039/C9CC06496F.
  • A. König, D. Schölzel, B. Uluca, T. Viennet, Ü. Akbey, H. Heise, Hyperpolarized MAS NMR of unfolded and misfolded proteins, Solid State NMR, 2019, 98, 1-11.
  • B. Uluca, T. Viennet, D. Petrović, H. Shaykhalishahi, F. Weirich, A. Gönülalan, B. Strodel, M. Etzkorn, W. Hoyer, and H. Heise. DNP-Enhanced solid-state NMR at Cryogenic Temperatures: a Tool to Snapshot Conformational Ensembles of α-Synuclein in Different States. Biophys. J. 2018, 114, 1614-1623.
  • L. Gremer, D. Schölzel, C. Schenk, E. Reinartz, J. Labahn, R. Ravelli, M. Tusche, C. Lopez-Iglesias, W. Hoyer, H. Heise, D. Willbold, G. Schröder, Fibril structure of amyloid-ß(1-42) by cryo-electron microscopy, Science, 2017, 358, 116-119.
  • T. Viennet, A. Viegas, A. Kuepper, S. Arens, V. Gelev, O. Petrov, T. N. Grossmann, H. Heise, M. Etzkorn, Selective Protein Hyperpolarization in Cell Lysates Using Targeted Dynamic Nuclear Polarization. Angew. Chem. Int. Ed. Engl. 2016, 55, 10746-10750.
Forschungszentrum Juelich GmbH
52425 Juelich
Sitz der Gesellschaft: Juelich
Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498
Vorsitzender des Aufsichtsrats: MinDir Volker Rieke
Geschaeftsfuehrung: Prof. Dr.-Ing. Wolfgang Marquardt (Vorsitzender),
Karsten Beneke (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt,
Prof. Dr. Sebastian M. Schmidt

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Nov 13, 2019

Rutile dielectric loop-gap resonator for X-band EPR spectroscopy of small aqueous samples

Mett, Richard R., Jason W. Sidabras, James R. Anderson, Candice S. Klug, and James S. Hyde. “Rutile Dielectric Loop-Gap Resonator for X-Band EPR Spectroscopy of Small Aqueous Samples.” Journal of Magnetic Resonance 307 (October 2019): 106585.

The performance of a metallic microwave resonator that contains a dielectric depends on the separation between metallic and dielectric surfaces, which affects radio frequency currents, evanescent waves, and polarization charges. The problem has previously been discussed for an X-band TE011 cylindrical cavity resonator that contains an axial dielectric tube (Hyde and Mett, 2017). Here, a short rutile dielectric tube inserted into a loop-gap resonator (LGR) at X-band, which is called a dielectric LGR (dLGR), is considered. The theory is developed and experimental results are presented. It was found that a central sample loop surrounded by four ‘‘flux-return” loops (i.e., 5-loop–4-gap) is preferable to a 3-loop–2-gap configuration. For sufficiently small samples (less than 1 mL), a rutile dLGR is preferred relative to an LGR both at constant K (B1= Pl) and at constant incident power. Introduction of LGR technology to X-band EPR was a significant advance for site-directed spin labeling because of small sample size and high K. The rutile dLGR introduced in this work offers further extension to samples that can be as small as 50 nL when using typical EPR acquisition times.

Nov 11, 2019

TmDOTP: An NMR-based thermometer for magic angle spinning NMR experiments

Knowing the actual sample temperature in a solid-state NMR experiment is crucial in many ways. Many different approaches exist from measuring the chemical shift difference in spectra of ethylene glycol (solution-state NMR spectroscopy) to measuring the peak position in lead nitrate or the T1 relaxation times of KBr (solid-state NMR spectroscopy). All of these methods have their pros and cons. This approach using TmDOTP, having a temperature coefficient of 1ppm/K and being inert to biopolymers is a valuable addition to the ssNMR toolbox.

Zhang, Dongyu, Boris Itin, and Ann E. McDermott. “TmDOTP: An NMR-Based Thermometer for Magic Angle Spinning NMR Experiments.” Journal of Magnetic Resonance 308 (November 1, 2019): 106574.

Solid state NMR is a powerful tool to probe membrane protein structure and dynamics in native lipid membranes. Sample heating during solid state NMR experiments can be caused by magic angle spinning and radio frequency irradiation such heating produces uncertainties in the sample temperature and temperature distribution, which can in turn lead to line broadening and sample deterioration. To measure sample temperatures in real time and to quantify thermal gradients and their dependence on radio frequency irradiation or spinning frequency, we use the chemical shift thermometer TmDOTP, a lanthanide complex. The H6 TmDOTP proton NMR peak has a large chemical shift (−176.3 ppm at 275 K) and it is well resolved from the protein and lipid proton spectrum. Compared to other NMR thermometers (e.g., the proton NMR signal of water), the proton spectrum of TmDOTP, particularly the H6 proton line, exhibits very high thermal sensitivity and resolution. In MAS studies of proteoliposomes we identify two populations of TmDOTP with differing temperatures and dependency on the radio frequency irradiation power. We interpret these populations as arising from the supernatant and the pellet, which is sedimented during sample spinning. In this study, we demonstrate that TmDOTP is an excellent internal standard for monitoring real-time temperatures of biopolymers without changing their properties or obscuring their spectra. Real time temperature calibration is expected to be important for the interpretation of dynamics and other properties of biopolymers.