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Dynamic nuclear polarisation via the integrated solid effect I: theory #DNPNMR
Jan 16, 2017 - 6:09 PM - by nmrlearner
nmrlearner's Avatar From The DNP-NMR Blog:

Dynamic nuclear polarisation via the integrated solid effect I: theory #DNPNMR

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Henstra, A. and W.T. Wenckebach, Dynamic nuclear polarisation via the integrated solid effect I: theory. Mol. Phys., 2013. 112(13): p. 1761-1772.


https://doi.org/10.1080/00268976.2013.861936


In the hyperpolarisation method known as dynamic nuclear polarisation (DNP), a small amount of unpaired electron spins is added to the sample containing the nuclear spins and the polarisation of these unpaired electron spins is transferred to the nuclear spins by means of a microwave field. Traditional DNP uses weak continuous wave (CW) microwave fields, so perturbation methods can be used to calculate the polarisation transfer. A much faster transfer of the electron spin polarisation is obtained with the integrated solid effect (ISE) which uses strong pulsed microwave fields. As in nuclear orientation via electron spin locking, the polarisation transfer is coherent, similar to the coherence transfer between nuclear spins. This paper presents a theoretical approach to calculate this polarisation transfer. ISE is successfully used for a fast polarisation transfer from short-lived photo-excited triplet states to the surrounding nuclear spins in molecular crystals. These triplet states are strongly aligned in the photo-excitation process and do not require the low temperatures and strong magnetic fields needed to polarise the electron spins in traditional DNP. In the following paper, the theory is... [Read More]
0 Replies | 1 Views
Painting with gumtion: Accelerating art
Jan 15, 2017 - 7:53 PM - by nmrlearner
nmrlearner's Avatar Painting with gumtion: Accelerating art

J.W.M. Turner used gumtion to make his paintings dynamic. It wasn't simply that he was a dab hand with the brush, he literally used a mixture called gumtion comprising mastic resin with a lead acetate additive to make his oils flow more slicker and smoother across the canvas a spectroscopic study shows.

Read the rest at Spectroscopynow.com
0 Replies | 11 Views
[NMR paper] Structure and Dynamics of the Huntingtin Exon-1 N-Terminus: A*Solution NMR Perspective.
Jan 15, 2017 - 2:57 AM - by nmrlearner
nmrlearner's Avatar Structure and Dynamics of the Huntingtin Exon-1 N-Terminus: A*Solution NMR Perspective.

Related Articles Structure and Dynamics of the Huntingtin Exon-1 N-Terminus: A*Solution NMR Perspective.

J Am Chem Soc. 2017 Jan 13;:

Authors: Baias M, Smith PE, Shen K, Joachimiak LA, ?erko S, Ko?mi?ski W, Frydman J, Frydman L


Abstract
Many neurodegenerative diseases are characterized by misfolding and aggregation of an expanded polyglutamine tract (polyQ). Huntington's Disease, caused by expansion of the polyQ tract in exon 1 of the Huntingtin protein (Htt), is associated with aggregation and neuronal toxicity. Despite recent structural progress in understanding the structures of amyloid fibrils, little is known about the solution states of Htt in general, and about molecular details of their transition from soluble to aggregation-prone conformations in particular. This is an important question, given the increasing realization that toxicity may reside in soluble conformers. This study presents an approach that combines NMR with computational methods to elucidate the structural conformations of Htt Exon 1 in solution. Of particular focus was Htt's N17 domain sited N-terminal to the polyQ tract, which is key to enhancing aggregation and modulate Htt toxicity. Such in-depth structural study of Htt presents a number of unique challenges: the long homopolymeric polyQ tract contains nearly... [Read More]
0 Replies | 10 Views
[NMR paper] Analysis of the solution conformations of T4 lysozyme by paramagnetic NMR spectroscopy.
Jan 15, 2017 - 2:57 AM - by nmrlearner
nmrlearner's Avatar Analysis of the solution conformations of T4 lysozyme by paramagnetic NMR spectroscopy.

Related Articles Analysis of the solution conformations of T4 lysozyme by paramagnetic NMR spectroscopy.

Phys Chem Chem Phys. 2016 Feb 17;18(8):5850-9

Authors: Chen JL, Yang Y, Zhang LL, Liang H, Huber T, Su XC, Otting G

Abstract
A large number of crystal structures of bacteriophage T4 lysozyme (T4-L) have shown that it contains two subdomains, which can arrange in a compact conformation (closed state) or, in mutants of T4-L, more extended structures (open state). In solution, wild-type T4-L displays only a single set of nuclear magnetic resonance (NMR) signals, masking any conformational heterogeneity. To probe the conformational space of T4-L, we generated a site-specific lanthanide binding site by attaching 4-mercaptomethyl dipicolinic acid via a disulfide bond to Cys44 in the triple-mutant C54T/C97A/S44C of T4-L and measured pseudocontact shifts (PCS) and magnetically induced residual dipolar couplings (RDC). The data indicate that, in solution and in the absence of... [Read More]
0 Replies | 12 Views
Structureand Dynamics of the Huntingtin Exon-1N-Terminus: A*Solution NMR Perspective
Jan 14, 2017 - 6:24 AM - by nmrlearner
nmrlearner's Avatar Structureand Dynamics of the Huntingtin Exon-1N-Terminus: A*Solution NMR Perspective

Maria Baias, Pieter E. S. Smith, Koning Shen, Lukasz A. Joachimiak, Szymon Z?erko, Wiktor Koz?min?ski, Judith Frydman and Lucio Frydman



Journal of the American Chemical Society
DOI: 10.1021/jacs.6b10893




Source: Journal of the American Chemical Society
0 Replies | 14 Views
[NMR paper] Folding of apomyoglobin: Analysis of transient intermediate structure during refolding using quick hydrogen deuterium exchange and NMR.
Jan 14, 2017 - 6:24 AM - by nmrlearner
nmrlearner's Avatar Folding of apomyoglobin: Analysis of transient intermediate structure during refolding using quick hydrogen deuterium exchange and NMR.

Related Articles Folding of apomyoglobin: Analysis of transient intermediate structure during refolding using quick hydrogen deuterium exchange and NMR.

Proc Jpn Acad Ser B Phys Biol Sci. 2017;93(1):10-27

Authors: Nishimura C

Abstract
The structures of apomyoglobin folding intermediates have been widely analyzed using physical chemistry methods including fluorescence, circular dichroism, small angle X-ray scattering, NMR, mass spectrometry, and rapid mixing. So far, at least two intermediates (on sub-millisecond- and millisecond-scales) have been demonstrated for apomyoglobin folding. The combination of pH-pulse labeling and NMR is a useful tool for analyzing the kinetic intermediates at the atomic level. Its use has revealed that the latter-phase kinetic intermediate of apomyoglobin (6 ms) was composed of helices A, B, G and H, whereas the equilibrium intermediate, called the pH 4 molten-globule intermediate, was composed mainly of helices A, G... [Read More]
0 Replies | 15 Views
Insight into the Supramolecular Architecture of Intact Diatom Biosilica from DNP-Supported Solid-State NMR Spectroscopy #DNPNMR
Jan 14, 2017 - 6:24 AM - by nmrlearner
nmrlearner's Avatar From The DNP-NMR Blog:

Insight into the Supramolecular Architecture of Intact Diatom Biosilica from DNP-Supported Solid-State NMR Spectroscopy #DNPNMR

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Jantschke, A., et al., Insight into the Supramolecular Architecture of Intact Diatom Biosilica from DNP-Supported Solid-State NMR Spectroscopy. Angew Chem Int Ed Engl, 2015. 54(50): p. 15069-73.


https://www.ncbi.nlm.nih.gov/pubmed/26509491


Diatom biosilica is an inorganic/organic hybrid with interesting properties. The molecular architecture of the organic material at the atomic and nanometer scale has so far remained unknown, in particular for intact biosilica. A DNP-supported ssNMR approach assisted by microscopy, MS, and MD simulations was applied to study the structural organization of intact biosilica. For the first time, the secondary structure elements of tightly biosilica-associated native proteins in diatom biosilica were characterized in situ. Our data suggest that these proteins are rich in a limited set of amino acids and adopt a mixture of random-coil and beta-strand conformations. Furthermore, biosilica-associated long-chain polyamines and carbohydrates were characterized, thereby leading to a model for the supramolecular organization of intact biosilica.
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Go to ... [Read More]
0 Replies | 15 Views
[NMR] MOOC on NMR, Feb. 20 to Apr. 17, 2017
Jan 14, 2017 - 6:24 AM - by nmrlearner
nmrlearner's Avatar From The DNP-NMR Blog:

[NMR] MOOC on NMR, Feb. 20 to Apr. 17, 2017

From the Ampere Magnetic Resonance List






Dear colleagues,


In 2015, the Massive Open Online Course (MOOC) “Nuclear Magnetic Resonance (NMR), a Compass to Nanoworld” hosted on the FUN platform was one of the first MOOCs covering the subject of NMR.


It is our great pleasure to announce that the second! offering of this MOOC is now open for free registration.


This MOOC in English aims at providing the basic knowledge about NMR and an overview of its applications to students and professionals who want to enter this field.


Topics to be covered include:


• Basic principles and practice of NMR spectroscopy;
• Solution NMR of small molecules;
• NMR of proteins and sugars;
• Basic principles and practice of solid-state NMR spectro scopy;
• NMR characterization of materials (glasses, heterogeneous catalysts, battery materials).


The courses will be held from February 20 to April 17, 2017. For this course, about 2-3 hours of work per week are expected. MOOC participants will learn through video lectures and online discussions with peers and professors. The acquired knowledge will be tested through weekly quizzes.


This course does not require previous knowledge about NMR spectroscopy. Nevertheless, the participants should have a background in basic chemistry (chemical elements, molecular structure) and in basic physics (magnetism, basic spectroscopy).


The teachers of this MOOC are Olivier Lafon (coordinator), Cédric Lion, Emmanuel... [Read More]
0 Replies | 30 Views
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