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Solid State Nuclear Magnetic Resonance

Patrick C A van der Wel
The aggregation of proteins and peptides into a variety of insoluble, and often non-native, aggregated states plays a central role in many devastating diseases. Analogous processes undermine the efficacy of polypeptide-based biological pharmaceuticals, but are also being leveraged in the design of biologically inspired self-assembling materials. This Trends article surveys the essential contributions made by recent solid-state NMR (ssNMR) studies to our understanding of the structural features of polypeptide aggregates, and how such findings are informing our thinking about the molecular mechanisms of misfolding and aggregation...
October 4, 2017: Solid State Nuclear Magnetic Resonance
Scott Sneddon, Jürgen Kahr, Angelica F Orsi, David J Price, Daniel M Dawson, Paul A Wright, Sharon E Ashbrook
Zeolitic imidazolate frameworks (ZIFs) are a subclass of metal-organic frameworks (MOFs) with extended three-dimensional networks of transition metal nodes (bridged by rigid imidazolate linkers), with potential applications in gas storage and separation, sensing and controlled delivery of drug molecules. Here, we investigate the use of (13)C and (15)N solid-state NMR spectroscopy to characterise the local structure and disorder in a variety of single- and dual-linker ZIFs. In most cases, a combination of a basic knowledge of chemical shifts typically observed in solution-state NMR spectroscopy and the use of dipolar dephasing NMR experiments to reveal information about quaternary carbon species are combined to enable spectral assignment...
September 9, 2017: Solid State Nuclear Magnetic Resonance
Y Nishiyama, M Malon, M J Potrzebowski, P Paluch, J P Amoureux
No abstract text is available yet for this article.
September 1, 2017: Solid State Nuclear Magnetic Resonance
Rasmus Linser
Solid-state NMR is able to generate structural data on sample preparations that are explicitly non-crystalline. In particular, for amyloid fibril samples, which can comprise significant degrees of sample disorder, solid-state NMR has been used very successfully. But also solid-state NMR studies of other supramolecular assemblies that have resisted assessment by more standard methods are being performed with increasing ease and biological impact, many of which are briefly reviewed here. New technical trends with respect to structure calculation, protein dynamics and smaller sample amounts have reshaped the field of solid-state NMR recently...
August 24, 2017: Solid State Nuclear Magnetic Resonance
Hiroki Nagashima, Julien Trébosc, Olivier Lafon, Frédérique Pourpoint, Piotr Paluch, Marek J Potrzebowski, Jean-Paul Amoureux
We investigate using nutation experiments the spatial distribution of radiofrequency (rf) field, sample, temperature and cross-polarization transfer efficiency in 1.3 mm rotor. First, two-dimensional (2D) (1)H nutation experiments on silicone thin cylinders in the presence of B0 field gradient generated by shim coils are used to image the spatial distribution of rf field inside the rotor. These experiments show that the rf field is asymmetrical with respect to the center of the rotor. Moreover, they show the large inhomogeneity that still remains across the sample when using spacers, and that even in this case, the rf-field close to the drive cap is decreased to ca...
August 12, 2017: Solid State Nuclear Magnetic Resonance
Takeshi Kobayashi, Frédéric A Perras, Umesh Chaudhary, Igor I Slowing, Wenyu Huang, Aaron D Sadow, Marek Pruski
We demonstrate that dynamic nuclear polarization (DNP)-enhanced (1)H-X heteronuclear correlation (HETCOR) measurements of hydrogen-rich surface species are better accomplished by using proton-free solvents. This approach notably prevents HETCOR spectra from being obfuscated by the solvent-derived signals otherwise present in DNP measurements. Additionally, in the hydrogen-rich materials studied here, which included functionalized mesoporous silica nanoparticles and metal organic frameworks, the use of proton-free solvents afforded higher sensitivity gains than the commonly used solvents containing protons...
August 12, 2017: Solid State Nuclear Magnetic Resonance
Diane Cala-De Paepe, Jan Stanek, Kristaps Jaudzems, Kaspars Tars, Loren B Andreas, Guido Pintacuda
(1)H-detection in solid-state NMR of proteins has been traditionally combined with deuteration for both resolution and sensitivity reasons, with the optimal level of proton dilution being dependent on MAS rate. Here we present (1)H-detected (15)N and (13)C CP-HSQC spectra on two microcrystalline samples acquired at 60 and 111 kHz MAS and at ultra-high field. We critically compare the benefits of three labeling schemes yielding different levels of proton content in terms of resolution, coherence lifetimes and feasibility of scalar-based 2D correlations under these experimental conditions...
July 25, 2017: Solid State Nuclear Magnetic Resonance
Xiaoyue Zhou, Kaipin Xu, Pei Ni, Qun Chen, Shanmin Zhang
Most of the polymers are composed of a crystal part, an amorphous part, and a transitional interfacial part. These components present disparate physical and chemical characteristics. However, it always suffers from peak overlapping in solid NMR spectrum in order to acquire polymer's crystallinity. The polyethylene oxide (PEO) sample was tested using the Torchia pulse sequence combined with the Multivariate Curve Resolution (MCR) method. A two dimensional CP/MAS spectrum containing spin-lattice relaxation time (T1) information was acquired...
September 2017: Solid State Nuclear Magnetic Resonance
Christophe Odin
In NMR, the repetition of pulse sequences with a recycle time that does not allow the spin system to completely relax back to equilibrium is a well known and often used method to increase the signal to noise ratio at given total measuring time. For isolated spins I=1/2, the steady-state of a train of strictly identical pulse sequences separated by free evolution periods of same duration is described by the well known Ernst-Anderson model, and the optimum pulse angle is given by the Ernst angle. We showed recently that equivalent formula, but with super-operators in the Liouville space, can be obtained for general spins I...
September 2017: Solid State Nuclear Magnetic Resonance
Paul Jonsen
During August 2015, the author surveyed 76 solid state NMR scientists from materials science to biology, academic to industrial, based in North America, Europe, India, China, Japan and Australia. The subject concerned barriers to the wider acceptance of solid state NMR and included the various barriers based on experimental, funding, vendor based and community aspects. This survey was confidential. However, many of the survey participants requested that at least the results of the part of the survey relevant to our community be made public...
September 2017: Solid State Nuclear Magnetic Resonance
K Seleznyova, N A Sergeev, M Olszewski, P Stępień, S V Yagupov, M B Strugatsky, J Kliava
A comparative analysis of the Czjzek's and Maurer's models of the joint distribution density of NMR quadrupole parameters has been carried out in view of their application to account for spectra broadening induced by local disorder in crystals. As an example of such an application, we have considered Magic Angle Spinning NMR of (11)B and (71)Ga isotopes in polycrystalline gallium borate. Computer simulations carried out using both models unambiguously show that in the case of low local disorder the Maurer's model, in contrast to the Czjzek's model, provides satisfactory fits to experimental NMR spectra...
September 2017: Solid State Nuclear Magnetic Resonance
Peter A Beckmann, Joseph M Bohen, Jamie Ford, William P Malachowski, Clelia W Mallory, Frank B Mallory, Andrew R McGhie, Arnold L Rheingold, Gilbert J Sloan, Steven T Szewczyk, Xianlong Wang, Kraig A Wheeler
We report a variety of experiments and calculations and their interpretations regarding methyl group (CH3) rotation in samples of pure 3-methylglutaric anhydride (1), pure 3-methylglutaric acid (2), and samples where the anhydride is slowly absorbing water from the air and converting to the acid [C6H8O3(1) + H2O → C6H10O4(2)]. The techniques are solid state (1)H nuclear magnetic resonance (NMR) spin-lattice relaxation, single-crystal X-ray diffraction, electronic structure calculations in both isolated molecules and in clusters of molecules that mimic the crystal structure, field emission scanning electron microscopy, differential scanning calorimetry, and high resolution (1)H NMR spectroscopy...
September 2017: Solid State Nuclear Magnetic Resonance
Syed Awais Rouf, Vibe Boel Jakobsen, Jiří Mareš, Nicholai Daugaard Jensen, Christine J McKenzie, Juha Vaara, Ulla Gro Nielsen
Recent advances in computational methodology allowed for first-principles calculations of the nuclear shielding tensor for a series of paramagnetic nickel(II) acetylacetonate complexes, [Ni(acac)2L2] with L = H2O, D2O, NH3, ND3, and PMe2Ph have provided detailed insight into the origin of the paramagnetic contributions to the total shift tensor. This was employed for the assignment of the solid-state (1,2)H and (13)C MAS NMR spectra of these compounds. The two major contributions to the isotropic shifts are by orbital (diamagnetic-like) and contact mechanism...
July 17, 2017: Solid State Nuclear Magnetic Resonance
Shigenobu Hayashi, Keiko Jimura
Mechanisms of the (1)H spin-lattice relaxation in NH4H2PO4 were studied in detail by use of the effect of magic angle spinning on the relaxation. The acid and the ammonium protons have different relaxation times at the spinning rates higher than 10 kHz due to suppression of spin diffusion between the two kinds of protons. The intrinsic relaxation times not affected by the spin diffusion and the spin-diffusion assisted relaxation times were evaluated separately, taking into consideration temperature dependence...
July 8, 2017: Solid State Nuclear Magnetic Resonance
Jochem Struppe, Caitlin M Quinn, Manman Lu, Mingzhang Wang, Guangjin Hou, Xingyu Lu, Jodi Kraus, Loren B Andreas, Jan Stanek, Daniela Lalli, Anne Lesage, Guido Pintacuda, Werner Maas, Angela M Gronenborn, Tatyana Polenova
The recent breakthroughs in NMR probe technologies resulted in the development of MAS NMR probes with rotation frequencies exceeding 100 kHz. Herein, we explore dramatic increases in sensitivity and resolution observed at MAS frequencies of 110-111 kHz in a novel 0.7 mm HCND probe that enable structural analysis of fully protonated biological systems. Proton- detected 2D and 3D correlation spectroscopy under such conditions requires only 0.1-0.5 mg of sample and a fraction of time compared to conventional (13)C-detected experiments...
July 3, 2017: Solid State Nuclear Magnetic Resonance
D Iuga, P Rossi, J Herzfeld, R G Griffin
Chloride ions play important roles in many chemical and biological processes. This paper investigates the possibility of localizing (35)Cl nuclei using solid-state NMR. It demonstrates that distances shorter than 3.8Å, between (13)C atoms and (35)Cl atoms in 10% uniformly labeled (13)C L-tyrosine·HCl and natural abundance Glycine·HCl can be measured using rotational-echo (adiabatic passage) double-resonance (RE(AP)DOR). Furthermore the effect of quadrupolar interaction on the REDOR/REAPDOR experiment is quantified...
July 2017: Solid State Nuclear Magnetic Resonance
Takahiro Iijima, Tadashi Shimizu
We examined a simple two-dimensional (2)H nuclear magnetic resonance spectroscopy for paramagnetic solids utilizing off-magic-angle spinning (OMAS). By adding a rotor-synchronized 180° pulse to rotational echo (RE) measurement, the effect of the shift interaction was removed from the indirect dimension. The obtained pure-quadrupole spectrum could be simulated by calculating a quasi-one-dimensional NMR signal without considering the shift interaction. The sensitivity of the proposed method was compared with that of previous static NMR methods...
July 2017: Solid State Nuclear Magnetic Resonance
Pedro B Groszewicz, Hergen Breitzke, Gerd Buntkowsky
The spinning sidebands envelope of satellite transitions often display an asymmetric shape, which is caused by an asymmetric response of the NMR probe circuit. In this work, we revisit the basic concepts of the RLC circuit at the heart of every NMR probe and present two approaches capable of minimizing this artifact. While the first one consists of deliberately mistuning the probe, the second one relies on measuring the probe's response function and deconvoluting its contribution from the spectra. Both approaches are validated with (23)Na NMR spectra of a lead-free relaxor ferroelectric (BNT-1BT)...
July 2017: Solid State Nuclear Magnetic Resonance
Hiroki Nagashima, Aany Sofia Lilly Thankamony, Julien Trébosc, Frédérique Pourpoint, Olivier Lafon, Jean Paul Amoureux
We introduce novel sequences using indirect detection to correlate quadrupolar nuclei and spin-1/2 isotopes, other than (1)H and (19)F. These sequences use γ-encoded symmetry-based RNn(ν) schemes that reintroduce the space component |m| = 1 of the heteronuclear dipolar coupling. These schemes can be applied to the indirectly detected spin in Dipolar-mediated Heteronuclear Multiple-Quantum Correlation (D-HMQC) sequence or to the detected isotope in a novel sequence, named Dipolar-mediated Heteronuclear Universal-Quantum Correlation (D-HUQC)...
July 2017: Solid State Nuclear Magnetic Resonance
Olivier Lafon
No abstract text is available yet for this article.
July 2017: Solid State Nuclear Magnetic Resonance
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