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This Is The Closest Look We've Ever Had at The Proteins Linked to Alzheimer's Disease - ScienceAlert
Sep 12, 2017 - 1:45 PM - by nmrlearner
nmrlearner's Avatar This Is The Closest Look We've Ever Had at The Proteins Linked to Alzheimer's Disease - ScienceAlert


ScienceAlert


This Is The Closest Look We've Ever Had at The Proteins Linked to Alzheimer's Disease
ScienceAlert
Extra readings from solid-state nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction experiments helped to validate the data and the atomic structure, producing a computer rendering that's the most accurate we've ever seen, down to a ...

... [Read More]
0 Replies | 56 Views
Overhauser-enhanced magnetic resonance elastography
Sep 12, 2017 - 12:56 AM - by nmrlearner
nmrlearner's Avatar From The DNP-NMR Blog:

Overhauser-enhanced magnetic resonance elastography

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Salameh, N., et al., Overhauser-enhanced magnetic resonance elastography. NMR in Biomedicine, 2016. 29(5): p. 607-613.


http://dx.doi.org/10.1002/nbm.3499


Magnetic resonance elastography (MRE) is a powerful technique to assess the mechanical properties of living tissue. However, it suffers from reduced sensitivity in regions with short T2 and T2* such as in tissue with high concentrations of paramagnetic iron, or in regions surrounding implanted devices. In this work, we exploit the longer T2* attainable at ultra-low magnetic fields in combination with Overhauser dynamic nuclear polarization (DNP) to enable rapid MRE at 0.0065 T. A 3D balanced steady-state free precession based MRE sequence with undersampling and fractional encoding was implemented on a 0.0065 T MRI scanner. A custom-built RF coil for DNP and a programmable vibration system for elastography were developed. Displacement fields and stiffness maps were reconstructed from data recorded in a polyvinyl alcohol gel phantom loaded with stable nitroxide radicals. A DNP enhancement of 25 was achieved during the MRE sequence, allowing the acquisition of 3D Overhauser-enhanced MRE (OMRE) images with (1.5 × 2.7 × 9) mm3 resolution over eight temporal steps and 11 slices in 6 minutes. In conclusion, OMRE at ultra-low magnetic field can be used to detect mechanical waves over short... [Read More]
0 Replies | 28 Views
[NMR] Faculty position at New York University
Sep 12, 2017 - 12:56 AM - by nmrlearner
nmrlearner's Avatar From The DNP-NMR Blog:

[NMR] Faculty position at New York University

From the Ampere Magnetic Resonance List






Dear Colleagues,

The Department of Chemistry at New York University is soliciting applications for faculty positions in Chemistry. One of the emphasis areas is biophysical chemistry, which may include NMR or EPR. The deadline for the application is Sep 29, 2017. The full search advertisement is copied and pasted below, and can also be found via the link: http://as.nyu.edu/chemistry/recruitment.html


best wishes,
Nate


----

ASSISTANT PROFESSOR

Department of Chemistry
Arts and Science
New York University

The Department of Chemistry at New York University (NYU) invites applications for several tenure-track faculty positions in all areas of Chemistry and Biochemistry, subject to final administrative approval. Successful candidates must have a Ph.D in chemistry or related field and demonstrate the potential to do pioneering research and to teach effectively at the undergraduate and graduate levels. The positions are anticipated to be at the junior level, although exceptional senior level candidates will be considered. The Department of Chemistry is continuing a significant growth plan, including the creation of the Biomedical Chemistry Institute, the Molecular Design Institute, and the addition of numerous senior and junior faculty members. Interested faculty are able to participate in... [Read More]
0 Replies | 43 Views
Protein Structure Determination - News-Medical.net
Sep 11, 2017 - 12:36 PM - by nmrlearner
nmrlearner's Avatar Protein Structure Determination - News-Medical.net



Protein Structure Determination
News-Medical.net
Cryoelectron microscopy is a variant at temperatures at or below that of liquid nitrogen and can visualize protein structures at very high resolution, though is less than that of methods like NMR spectroscopy or crystallography. It works with minute ...


Read here
0 Replies | 48 Views
[NMR paper] Label-free quantitative 1H NMR spectroscopy to study low-affinity ligand-protein interactions in solution: A contribution to the mechanism of polyphenol-mediated astringency.
Sep 09, 2017 - 6:59 PM - by nmrlearner
nmrlearner's Avatar Label-free quantitative 1H NMR spectroscopy to study low-affinity ligand-protein interactions in solution: A contribution to the mechanism of polyphenol-mediated astringency.

Label-free quantitative 1H NMR spectroscopy to study low-affinity ligand-protein interactions in solution: A contribution to the mechanism of polyphenol-mediated astringency.

PLoS One. 2017;12(9):e0184487

Authors: Delius J, Frank O, Hofmann T

Abstract
Nuclear magnetic resonance (NMR) spectroscopy is well-established in assessing the binding affinity between low molecular weight ligands and proteins. However, conventional NMR-based binding assays are often limited to small proteins of high purity and may require elaborate isotopic labeling of one of the potential binding partners. As protein-polyphenol complexation is assumed to be a key event in polyphenol-mediated oral astringency, here we introduce a label-free, ligand-focused 1H NMR titration assay to estimate binding affinities and characterize soluble complex formation between proteins and low molecular weight polyphenols. The method makes use of the effects of NMR line broadening due to protein-ligand interactions and quantitation of the non-bound ligand at varying protein concentrations by quantitative 1H NMR spectroscopy (qHNMR) using electronic reference to access in vivo concentration (ERETIC 2). This technique is applied to assess the interaction kinetics of selected astringent tasting polyphenols and purified mucin, a major lubricating glycoprotein of human saliva, as well as human whole saliva. The protein affinity values (BC50) obtained are subsequently correlated with the intrinsic mouth-puckering,... [Read More]
0 Replies | 35 Views
[NMR paper] Prediction of nearest neighbor effects on backbone torsion angles and NMR scalar coupling constants in disordered proteins.
Sep 09, 2017 - 6:59 PM - by nmrlearner
nmrlearner's Avatar Prediction of nearest neighbor effects on backbone torsion angles and NMR scalar coupling constants in disordered proteins.

Prediction of nearest neighbor effects on backbone torsion angles and NMR scalar coupling constants in disordered proteins.

Protein Sci. 2017 Sep 08;:

Authors: Shen Y, Roche J, Grishaev A, Bax A

Abstract
Using fine-tuned hydrogen bonding criteria, a library of coiled peptide fragments has been generated from a large set of high-resolution protein X-ray structures. This library is shown to be an improved representation of ?/? torsion angles seen in intrinsically disordered proteins (IDPs). The ?/? torsion angle distribution of the library, on average, provides good agreement with experimentally observed chemical shifts and (3) JHN-H? coupling constants for a set of five disordered proteins. Inspection of the coil library confirms that nearest-neighbor effects significantly impact the ?/? distribution of residues in the coil state. Importantly, (3) JHN-H? coupling constants derived from the nearest-neighbor modulated backbone ? distribution in the coil library show improved agreement to experimental values, thereby providing a better way to predict (3) JHN-H? coupling constants for IDPs, and for identifying locations that deviate from fully random behavior. This article is protected by copyright. All rights reserved.


PMID: 28884933 [PubMed - as supplied by publisher]



... [Read More]
0 Replies | 48 Views
Optimization of 1 H decoupling eliminates sideband artifacts in 3D TROSY-based triple resonance experiments
Sep 09, 2017 - 2:06 AM - by nmrlearner
nmrlearner's Avatar Optimization of 1 H decoupling eliminates sideband artifacts in 3D TROSY-based triple resonance experiments

Abstract

TROSY-based triple resonance experiments are essential for protein backbone assignment of large biomolecular systems by solution NMR spectroscopy. In a survey of the current Bruker pulse sequence library for TROSY-based experiments we found that several sequences were plagued by artifacts that affect spectral quality andĀ*hamper data analysis. Specifically, these experiments produce sidebands in the 13C(t 1) dimension with inverted phase corresponding to 1HN resonance frequencies, with approximately 5% intensity of the parent 13C crosspeaks. These artifacts originate from the modulation of the 1HN frequency onto the resonance frequency of 13CĪ± and/or 13CĪ² and are due to 180Ā° pulses imperfections used for 1H decoupling during the 13C(t 1) evolution period. These sidebands can become severe for CAi, CAiā??1 and/or CBi, CBiā??1 correlation experiments such as TROSY-HNCACB. Here, we implement three alternative decoupling strategies that suppress these artifacts and, depending on the scheme employed, boost the sensitivity up to 14% on Bruker spectrometers. A class of comparable Agilent/Varian pulse sequences that use WALTZ16 1H decoupling can also be improved by this method resulting in up to 60ā??80% increase in sensitivity.



Source: Journal of Biomolecular NMR
0 Replies | 32 Views
Near-unity nuclear polarization with an open-source 129Xe hyperpolarizer for NMR and MRI
Sep 09, 2017 - 2:06 AM - by nmrlearner
nmrlearner's Avatar From The DNP-NMR Blog:

Near-unity nuclear polarization with an open-source 129Xe hyperpolarizer for NMR and MRI

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Already a bit older this article, but still a good read.




Nikolaou, P., et al., Near-unity nuclear polarization with an open-source 129Xe hyperpolarizer for NMR and MRI. Proc. Nat. Aca. Sci. USA, 2013. 110(35): p. 14150-14155.


http://www.pnas.org/content/110/35/14150.abstract


The exquisite NMR spectral sensitivity and negligible reactivity of hyperpolarized xenon-129 (HP129Xe) make it attractive for a number of magnetic resonance applications; moreover, HP129Xe embodies an alternative to rare and nonrenewable 3He. However, the ability to reliably and inexpensively produce large quantities of HP129Xe with sufficiently high 129Xe nuclear spin polarization (PXe) remains a significant challenge—particularly at high Xe densities. We present results from our “open-source” large-scale (~1 L/h) 129Xe polarizer for clinical, preclinical, and materials NMR and MRI research. Automated and composed mostly of off-the-shelf components, this “hyperpolarizer” is designed to be readily implementable in other laboratories. The device runs with high resonant photon flux (up to 200 W at the Rb D1 line) in the xenon-rich regime (up to 1,800 torr Xe in 500 cc) in either single-batch or stopped-flow mode, negating in part the usual requirement of Xe cryocollection. Excellent... [Read More]
0 Replies | 33 Views
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