Category Archives: solid-state NMR

ssNMR/DNP ZOOMinar (4/29) : Matthias Ernst and Songi Han #DNPNMR

From the ssNMR mailing list

Date: Sun, 26 Apr 2020 15:10:25 +0000

From: Kong Ooi Tan <kongooi@mit.edu>

Subject: [ssNMR] ssNMR/DNP ZOOMinar (4/29) : Matthias Ernst and Songi Han

Hi all,

I would like to announce our second ZOOMinar session on 4/29, Wed 11 am Boston / 5 pm Zurich / 8 am California. Our speakers are Prof. Matthias Ernst (ETHZ) and Prof. Songi Han (UCSB), the details are:

Zoom link: https://mit.zoom.us/j/91253458660 <https://mit.zoom.us/j/91253458660>

Duration: 1 hr, i.e. 30 mins (23 mins talk + 7 mins Q&A) per speaker

1st speaker: Matthias Ernst, ?Residual Line Width in FSLG Decoupled Proton MAS Spectra?

Recorded (Yes/No): No

-PhD studies with Prof. Richard R. Ernst at ETHZ.

-Postdoc with Prof. Alex Pines at UC Berkeley for 2 years

-Staff scientist with Prof. Beat H. Meier at University of Nijmegen

-Joined ETHZ as a senior scientist in Beat?s group, and promoted to adjunct Professor in 2011.

2nd speaker: Songi Han, ?Asymmetry in Electron Spin Polarization and Coupling drives Cross-Effect and Thermal Mixing DNP?

Recorded (Yes/No): Yes

She received her Doctoral Degree from Aachen University of Technology (RWTH), Germany, in 2001. She pursued her postdoctoral studies at the Max-Planck Institute for Polymer Research, Mainz, and the University of California Berkeley. She joined the faculty at UCSB in 2004, and was promoted to full professor in 2012.

Regards,

Kong

Dr. Kong Ooi Tan

Postdoctoral Fellow

Francis Bitter Magnet Laboratory

Massachusetts Institute of Technology

77 Massachusetts Avenue, NW14-4112

Cambridge, MA 02139

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Structure determination of supra-molecular assemblies by solid-state NMR: Practical considerations #DNPNMR

Demers, Jean-Philippe, Pascal Fricke, Chaowei Shi, Veniamin Chevelkov, and Adam Lange. “Structure Determination of Supra-Molecular Assemblies by Solid-State NMR: Practical Considerations.” Progress in Nuclear Magnetic Resonance Spectroscopy 109 (December 2018): 51–78.

https://doi.org/10.1016/j.pnmrs.2018.06.002

In the cellular environment, biomolecules assemble in large complexes which can act as molecular machines. Determining the structure of intact assemblies can reveal conformations and inter-molecular interactions that are only present in the context of the full assembly. Solid-state NMR (ssNMR) spectroscopy is a technique suitable for the study of samples with high molecular weight that allows the atomic structure determination of such large protein assemblies under nearly physiological conditions.

This review provides a practical guide for the first steps of studying biological supramolecular assemblies using ssNMR. The production of isotope-labeled samples is achievable via several means, which include recombinant expression, cell-free protein synthesis, extraction of assemblies directly from cells, or even the study of assemblies in whole cells in situ. Specialized isotope labeling schemes greatly facilitate the assignment of chemical shifts and the collection of structural data. Advanced strategies such as mixed, diluted, or segmental subunit labeling offer the possibility to study inter-molecular interfaces.

Detailed and practical considerations are presented with respect to first setting up magicangle spinning (MAS) ssNMR experiments, including the selection of the ssNMR rotor, different methods to best transfer the sample and prepare the rotor, as well as common and robust procedures for the calibration of the instrument. Diagnostic spectra to evaluate the resolution and sensitivity of the sample are presented. Possible improvements that can reduce sample heterogeneity and improve the quality of ssNMR spectra are reviewed.

Solid state NMR service across the world #ssNMR

This article is not directly about DNP-NMR spectroscopy. However, since DNP is predominantly used in solid-state NMR spectroscopy it is interesting to see how solid-state NMR is becoming more popular across the worl.

Barrow, Nathan S., and Paul Jonsen. “Solid State NMR Service across the World.” Solid State Nuclear Magnetic Resonance 105 (February 2020): 101626. 

https://doi.org/10.1016/j.ssnmr.2019.101626

In 2013 the EPSRC published a report on the NMR equipment base serving the physical and life sciences community in the UK. Whilst this included both solution and solid state NMR, the report omitted equipment from industry or outside of the UK. This report originated as a means of benchmarking industrial solid state NMR facilities around the world. A survey of 24 SSNMR laboratories was conducted in the first half of 2019, primarily by face-to-face interviews or via telephone. Aggregated statistics relating to service throughput, equipment, and staff are presented, along with discussions about barriers to accessing SSNMR. We found that the hardware profile seen in the earlier UK-only report was representative of the worldwide view, and that the main barrier to access was a lack of knowledge about what SSNMR can do. Publishing this survey provides a strong benchmark for SSNMR laboratories, which will hopefully allow them to identify barriers that might be preventing them from performing to their optimal level in solving materials science problems.

High-sensitivity protein solid-state NMR spectroscopy #DNPNMR

Mandala, Venkata S, and Mei Hong. “High-Sensitivity Protein Solid-State NMR Spectroscopy.” Current Opinion in Structural Biology 58 (October 2019): 183–90.

https://doi.org/10.1016/j.sbi.2019.03.027

The sensitivity of solid-state nuclear magnetic resonance (SSNMR) spectroscopy for structural biology is significantly increased by 1H detection under fast magic-angle spinning (MAS) and by dynamic nuclear polarization (DNP) from electron spins to nuclear spins. The former allows studies of the structure and dynamics of small quantities of proteins under physiological conditions, while the latter permits studies of large biomolecular complexes in lipid membranes and cells, protein intermediates, and protein conformational distributions. We highlight recent applications of these two emerging SSNMR technologies and point out areas for future development.

[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 (http://nmr.ethz.ch), 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 (beme@ethz.ch)

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[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 (http://nmr.ethz.ch), 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 (beme@ethz.ch)

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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.

https://doi.org/10.1016/j.jmr.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.

Solid-state NMR of nanocrystals #DNPNMR

Gutmann, Torsten, Pedro B. Groszewicz, and Gerd Buntkowsky. “Solid-State NMR of Nanocrystals.” In Annual Reports on NMR Spectroscopy, 97:1–82. Elsevier, 2019.

https://doi.org/10.1016/bs.arnmr.2018.12.001

Recent advances in solid-state nuclear magnetic resonance (NMR) spectroscopy and dynamic nuclear polarization (DNP) of nanostructured materials are reviewed. A first group of materials is based on crystalline nanocellulose (CNC) or microcrystalline cellulose (MCC), which are used as carrier materials for dye molecules, catalysts or in combination with heterocyclic molecules as ion conducting membranes. These materials have widespread applications in sensorics, optics, catalysis or fuel cell research. A second group are metal oxides such as V-Mo-W oxides, which are of enormous importance in the manufacturing process of basic chemicals. The third group are catalytically active nanocrystalline metal nanoparticles, coated with protectants or embedded in polymers. The last group includes of lead-free perovskite materials, which are employed as environmentally benign substitution materials for conventional lead-based electronics materials. These materials are discussed in terms of their application and physicochemical characterization by solid-state NMR techniques, combined with gas-phase NMR and quantum-chemical modelling on the density functional theory (DFT) level. The application of multinuclear 1H, 2H, 13C, 15N and 23Na solid state NMR techniques under static or MAS conditions for the characterization of these materials, their surfaces and processes on their surfaces is discussed. Moreover, the analytic power of the combination of these techniques with DNP for the identification of low-concentrated carbon and nitrogen containing surface species in natural abundance is reviewed. Finally, approaches for sensitivity enhancement by DNP of quadrupolar nuclei such as 17O and 51V are presented that enable the identification of catalytic sites in metal oxide catalysts

[NMR] solid-state NMR postdoc position available

Dear NMR community;

A postdoctoral position is available in my laboratory at UC Irvine (please see attached description.) The project involves developing and using multidimensional sequences for incorporating 2H into protein structure determination experiments in solids, using our unique quadruple-resonance MAS probe operating at 800 MHz. Anyone who is interested should email Rachel Martin (rwmartin@uci.edu). The formal application can be found on UCI’s website at https://recruit.ap.uci.edu/JPF05254. I will also be at the Alpine conference in Chamonix if any potential candidates who are attending the meeting would like to discuss the project with me.

Best,

Rachel Martin

DESCRIPTION

School of Physical Sciences

Department of Chemistry

Position: Postdoctoral Position – Solid-State NMR

A postdoctoral position is available at the University of California, Irvine in the area of protein structure determination by solid-state NMR, specifically of the aggregates of eye lens proteins found in cataract disease. The goal of this NIH-funded project is to develop and use advanced solid-state NMR methods for the study of complicated protein aggregates. The group has access to an 800 MHz instrument, equipped with solution-state and MAS probes, including a unique crossed-coil 1H/13C/2H/15N MAS probe purpose-built for these experiments. We also have two dedicated 500 MHz NMR instruments (one solids and one liquids), as well as a fully-equipped molecular biology

laboratory for sample preparation. The ideal candidate will be experienced in protein structure determination by MAS and interested in using novel instrumentation to solve biological problems.

The project supports solid-state NMR methods development and structure determination of wild-type human γS-crystallin in the transparent hydrogel state found in the healthy eye lens, as well as the aggregates formed by UV-light damaged proteins and cataract-related variants. The Martin group is experienced in preparation of crystallin proteins: isotopically labeled samples of the transparent hydrogel of the native crystallin and the aggregates associated with cataract have been prepared. As part of this project, new NMR methodology will be developed to investigate the structural factors related to γS-crystallin stability and solubility. Differential isotope labeling of peptide binders and variant crystallins will be used to identify specific residues involved in altered intermolecular interactions, followed by full structure determination of cataract aggregates. Extensive use will be made of deuterated samples and deuterium NMR in the context of multidimensional NMR experiments.

Candidates must have (or be about to earn) a Ph.D. in Chemistry, Physics, or a related discipline, and have experience solving protein structures using MAS NMR. Previous experience with pulse sequence development is desirable but not required.

Please apply online at https://recruit.ap.uci.edu/apply/JPF05254 with a cover letter that also describes your immediate and long-term research goals, a curriculum vitae including publications list, and names for three letters of reference (please do not solicit letters). Review of applications will begin on Oct 1, 2019 and will continue until the position is filled.

The University of California, Irvine is an Equal Opportunity/Affirmative Action Employer advancing inclusive excellence. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, age, protected veteran status, or other protected categories covered by the UC nondiscrimination policy.

Rachel W. Martin

Professor of Chemistry

and Molecular Biology & Biochemistry

University of California, Irvine

rwmartin@uci.edu

probemonkey.com

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[NMR] PhD position at University of Lille – Solid-state NMR of optoelectronic materials #DNPNMR

University of Lille invites applications for a 3-year PhD position in the area of solid-state NMR of optoelectronic materials. The research project, funded by the University of Lille and the region Haute-de-France, will start from 1 October 2019. PhD student will be supervised by Dr. Manjunatha Reddy in close collaboration with Dr. Laurent Delevoye and Prof. Olivier Lafon at the Department of Chemistry, Solid-State Chemistry Division.

Send your application as a single pdf containing cover letter, CV and references, and transcripts directly to gnm.reddy@univ-lille.fr ; laurent.delevoye@univ-lille.fr ; olivier.lafon@univ-lille.fr before 31 May 2019. To be considered for this PhD positon the applicant must have (i) completed Master’s degree in Chemistry, Physics or Material Science by August 2019, (ii) experience in synthesis of hybrid materials into thin films and analyses by surface and bulk characterization techniques, and (iii) excellent communication skills in English. Proficiency in French language is a plus but not obligatory. For informal queries about the position please contact gnm.reddy@univ-lille.fr

Research project and objectives: The quest for developing high-performance materials for optoelectronics applications is growing faster than ever. Last decade has seen a spike in the development of π-conjugated materials and hybrid perovskite halides as low-cost and efficient solar absorbers, enabling power conversion efficiencies over 15% and 23%, respectively. Such advancements in material syntheses necessitate the requirement for in-depth analyses of reactive heterogeneous surfaces and interfaces, particularly at high sensitivity and resolution. The objectives of this project are to develop and acquire deep new understandings of structure-function relationships in optoelectronic materials. Notably, low-dimensional hybrid perovskite halides will be synthesized in the form of layered structures by incorporating organic and inorganic building blocks. The key is to combine solvothermal synthesis with in situ or ex situ solid-state NMR characterization techniques so as to gai!

n insight into the evolution of molecular order at organic-inorganic interfaces. Complementary information on the material compositions and structures will be obtained by X-ray and neutron scattering techniques, surface probes (electron microscopy and X-ray photoelectron spectroscopy) and depth profiling using secondary-ion mass spectrometry (SIMS). All of these fundamental understandings will be used to rationalize the material design in order to augment the stability, performance and propensity towards enhanced optical and electronic properties.

Host laboratory and infrastructure: Research will be carried out at the Department of Chemistry – Solid-state Chemistry Division, University of Lille. City of Lille is located in northwestern France, easily accessible from/to Paris, Brussels and London by train. Department of Chemistry offers excellent training courses and hosts state-of-the-art research facilities; synthesis chemistry apparatus and analytical facilities for surface and bulk characterization of materials. Of particularly relevant to this project, NMR center in Lille is equipped with high field (800 and 900 MHz) spectrometers and placed an order for a 1.2 GHz spectrometer for the characterization of material solids, which is a unique opportunity to undertake this interdisciplinary research project. 

Regards,

G. N. Manjunatha Reddy

Assistant Professor of Chemistry

Solid-State Chemistry Division

Ecole Nationale Supérieure de Chimie de Lille

Cité Scientifique, 218 Bâtiment C7-BP 90108

Villeneuve D’Ascq 59650 

France

Tel: +33 (0)3 2033 5907

http://uccs.univ-lille1.fr/index.php/en/directory/479-reddy-g-n-manjunatha

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