keyword
MENU ▼
Read by QxMD icon Read
search

EPR

keyword
https://www.readbyqxmd.com/read/27922050/identification-and-structural-characterization-of-the-n-terminal-amyloid-core-of-orb2-isoform-a
#1
Silvia A Cervantes, Thalia H Bajakian, Maria A Soria, Alexander S Falk, Rachel J Service, Ralf Langen, Ansgar B Siemer
Orb2 is a functional amyloid that plays a key role in Drosophila long-term memory formation. Orb2 has two isoforms that differ in their N-termini. The N-terminus of the A isoform (Orb2A) that precedes its Q-rich prion-like domain has been shown to be important for Orb2 aggregation and long-term memory. However, besides the fact that it forms fibrillar aggregates, structural information of Orb2 is largely absent. To understand the importance of the N-terminus of Orb2A and its relation to the fibril core, we recorded solid-state NMR and EPR data on fibrils formed by the first 88 residues of Orb2A (Orb2A88)...
December 6, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27921336/magnetic-anisotropy-in-pentacoordinate-ni-ii-and-co-ii-complexes-unraveling-electronic-and-geometrical-contributions
#2
Talal Mallah, Benjamin Cahier, Mauro Perfetti, Georges Zakhia, Daoud Naoufal, Fatima El-Khatib, Régis Guillot, Eric Rivière, Roberta Sessoli, Anne-Laure Barra, Nathalie Guihéry
The magnetic properties of the pentacoordinated [MII(Me4cyclam)N3]+ (Me4cyclam = tetramethylcyclam; N3 = azido and M = Ni and Co) complexes were investigated. Magnetization and EPR studies indicate that they possess an easy plane of magnetization with the axial anisotropy parameters D being close to 22 and larger than 30 cm-1 for the Ni and Co derivative, respectively. Ab initio calculations reproduce the experimental values of the zero field splitting parameters and allow determining the orientation of the anisotropy tensor axes with respect to the molecular frame...
December 6, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27920435/evolution-of-the-intrinsic-electronic-phase-separation-in-la0-6er0-1sr0-3mno3-perovskite
#3
Lili Chen, Jiyu Fan, Wei Tong, Dazhi Hu, Yanda Ji, Jindong Liu, Lei Zhang, Li Pi, Yuheng Zhang, Hao Yang
Magnetic and electronic transport properties of perovskite manganite La0.6Er0.1Sr0.3MnO3 have been thoroughly examined through the measurements of magnetization, electron paramagnetic resonance(EPR), and resistivity. It was found that the substitution of Er(3+) for La(3+) ions introduced the chemical disorder and additional strain in this sample. An extra resonance signal occurred in EPR spectra at high temperatures well above T C gives a strong evidence of electronic phase separation(EPS). The analysis of resistivity enable us to identify the polaronic transport mechanism in the paramagnetic region...
December 2016: Scientific Reports
https://www.readbyqxmd.com/read/27918131/a-redox-induced-spin-state-cascade-in-a-mixed-valent-fe3-%C3%AE-3-o-triangle
#4
Evgen V Govor, Karrar Al-Ameed, Indranil Chakraborty, Carla S Coste, Olena Govor, Yiannis Sanakis, John E McGrady, Raphael G Raptis
One-electron reduction of a pyrazolate-bridged triangular Fe3 (μ3 -O) core induces a cascade wherein all three metal centers switch from high-spin Fe(3+) to low-spin Fe(2.66+) . This hypothesis is supported by spectroscopic data ((1) H-NMR, UV-vis-NIR, infra-red, (57) Fe-Mössbauer, EPR), X-ray crystallographic characterization of the cluster in both oxidation states and also density functional theory. The reduction induces substantial contraction in all bond lengths around the metal centers, along with diagnostic shifts in the spectroscopic parameters...
December 5, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27918126/versatile-trityl-spin-labels-for-nanometer-distance-measurements-on-biomolecules-in%C3%A2-vitro-and-within-cells
#5
J Jacques Jassoy, Andreas Berndhäuser, Fraser Duthie, Sebastian P Kühn, Gregor Hagelueken, Olav Schiemann
Structure determination of biomacromolecules under in-cell conditions is a relevant yet challenging task. Electron paramagnetic resonance (EPR) distance measurements in combination with site-directed spin labeling (SDSL) are a valuable tool in this endeavor but the usually used nitroxide spin labels are not well-suited for in-cell measurements. In contrast, triarylmethyl (trityl) radicals are highly persistent, exhibit a long relaxation time and a narrow spectral width. Here, the synthesis of a versatile collection of trityl spin labels and their application in in vitro and in-cell trityl-iron distance measurements on a cytochrome P450 protein are described...
December 5, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27915179/axially-uniform-magnetic-field-modulation-excitation-for-electron-paramagnetic-resonance-in-rectangular-and-cylindrical-cavities-by-slot-cutting
#6
Jason W Sidabras, James E Richie, James S Hyde
In continuous-wave (CW) Electron Paramagnetic Resonance (EPR) a low-frequency time-harmonic magnetic field, called field modulation, is applied parallel to the static magnetic field and incident on the sample. Varying amplitude of the field modulation incident on the sample has consequences on spectral line-shape and line-height over the axis of the sample. Here we present a method of coupling magnetic field into the cavity using slots perpendicular to the sample axis where the slot depths are designed in such a way to produce an axially uniform magnetic field along the sample...
November 25, 2016: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/27915178/anticancer-copper-pyridine-benzimidazole-complexes-ros-generation-biomolecule-interactions-and-cytotoxicity
#7
Kathleen E Prosser, Stephanie W Chang, Felix Saraci, Phuc H Le, Charles J Walsby
The Cu(II) complex CuCl2(pbzH), pbzH=2-(2-pyridyl)benzimidazole, and derivatives modified at the non-coordinated nitrogen of the benzimidazole fragment, have been studied as anticancer agents. These compounds show promising cytotoxicity against A549 adenocarcinomic alveolar basal epithelial cells with IC50 values in the range of 5-10μM. Importantly, this activity is higher than either CuCl2·2H2O or the individual ligands, demonstrating that ligand coordination to the Cu(II) centres of the complexes is required for full activity...
November 5, 2016: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/27914342/cu3-btc-2-catalyzed-dehydrogenative-coupling-of-dimethylphenylsilane-with-phenol-and-homocoupling-of-dimethylphenylsilane-to-disiloxane
#8
Nagaraj Anbu, Amarajothi Dhakshinamoorthy
Cu3(BTC)2 (BTC: 1,3,5-benzenetricarboxylic acid) showed to be an efficient and reusable heterogeneous solid catalyst for the formation of SiO bond through dehydrogenative coupling of dimethylphenylsilane (1) with phenol under mild reaction conditions. It is observed that Fe(BTC), MIL-101(Cr) and UiO-66(Zr) are not able to promote this cross coupling between 1 and phenol. Cu3(BTC)2 exhibits higher stability and activity compared to other MOFs studied here. Furthermore, Cu3(BTC)2 is reused for three consecutive cycles with a slight decay in its activity...
November 24, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/27914267/intein-mediated-site-specific-synthesis-of-tumor-targeting-protein-delivery-system-turning-peg-dilemma-into-prodrug-like-feature
#9
Yingzhi Chen, Meng Zhang, Hongyue Jin, Yisi Tang, Huiyuan Wang, Qin Xu, Yaping Li, Feng Li, Yongzhuo Huang
Poor tumor-targeted and cytoplasmic delivery is a bottleneck for protein toxin-based cancer therapy. Ideally, a protein toxin drug should remain stealthy in circulation for prolonged half-life and reduced side toxicity, but turn activated at tumor. PEGylation is a solution to achieve the first goal, but creates a hurdle for the second because PEG rejects interaction between the drugs and tumor cells therein. Such PEG dilemma is an unsolved problem in protein delivery. Herein proposed is a concept of turning PEG dilemma into prodrug-like feature...
November 27, 2016: Biomaterials
https://www.readbyqxmd.com/read/27912180/radicals-formed-from-proton-loss-of-carotenoid-radical-cations-a-special-form-of-carotenoid-neutral-radical-occurring-in-photoprotection
#10
A Ligia Focsan, Lowell D Kispert
In an organized assembly in Arabidopsis thaliana plant, proton loss from the radical cation of zeaxanthin (Zea(+)) was found to occur under intense illumination, a possible component in photoprotection. A stable neutral radical is formed because of the favorable proton loss at C4(4') position(s) of the terminal ends of Zea(+) that extends the unpaired spin density distribution (notation Zea(4) or Zea(4') by symmetry). Proton loss from the radical cation of β-carotene (β-car(+)) to available proton acceptors was also detected in a PSII sample upon irradiation...
November 19, 2016: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/27911781/structure-and-mechanism-of-nov1-a-resveratrol-cleaving-dioxygenase
#11
Ryan P McAndrew, Noppadon Sathitsuksanoh, Michael M Mbughuni, Richard A Heins, Jose H Pereira, Anthe George, Kenneth L Sale, Brian G Fox, Blake A Simmons, Paul D Adams
Stilbenes are diphenyl ethene compounds produced naturally in a wide variety of plant species and some bacteria. Stilbenes are also derived from lignin during kraft pulping. Stilbene cleavage oxygenases (SCOs) cleave the central double bond of stilbenes, forming two phenolic aldehydes. Here, we report the structure of an SCO. The X-ray structure of NOV1 from Novosphingobium aromaticivorans was determined in complex with its substrate resveratrol (1.89 Å), its product vanillin (1.75 Å), and without any bound ligand (1...
November 30, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27910990/a-ph-responsive-sequential-disassembly-nanohybrid-for-mitochondrial-targeting
#12
Lijia Li, Wei Sun, Lian Li, Yuanyuan Liu, Lei Wu, Fengling Wang, Zhou Zhou, Zhirong Zhang, Yuan Huang
Cationic materials have been reported as promising tools for targeting to mitochondria which are the "power houses" and "metabolic garbage keepers" of cells. However, their positive nature also restricts their in vivo application due to the quick clearance. Herein, we fabricated a nanohybrid consisting of the pH-responsive N-(2-hydroxypropyl)methacrylamide (HPMA) co-polymer (R-P) shells and positive mesoporous silica nanoparticle cores via electrostatic interaction. The anticancer drug, docetaxel (DTX), was encapsulated in the positive MSN cores (MSN-DTX)...
December 2, 2016: Nanoscale
https://www.readbyqxmd.com/read/27907864/heterolytic-oo-bond-cleavage-functional-role-of-glu113-during-bis-fe-iv-formation-in-maug
#13
Jiafeng Geng, Lu Huo, Aimin Liu
The diheme enzyme MauG utilizes H2O2 to perform oxidative posttranslational modification on a protein substrate. A bis-Fe(IV) species of MauG was previously identified as a key intermediate in this reaction. Heterolytic cleavage of the OO bond of H2O2 drives the formation of the bis-Fe(IV) intermediate. In this work, we tested a hypothesis that a glutamate residue, Glu113 in the distal pocket of the pentacoordinate heme of MauG, facilitates heterolytic OO bond cleavage, thereby leading to bis-Fe(IV) formation...
November 9, 2016: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/27905382/-complexes-of-nitric-oxide-with-hemoglobin-and-paramagnetic-metalloenzymes-in-the-brain-and-blood-of-mammals-after-intermittent-hypoxia
#14
Z V Kuropteva, V P Reutov, L M Baider, A L Krushinsky
AIM: To investigate an effect of hypoxia on the formation of nitric oxide (NO) in the brain and blood of rats and an influence of L-NNA, the NO-synthase inhibitor, and sodium nitrite on NO generation in separate and simultaneous introduction of these compounds in the animal body. MATERIAL AND METHODS: Experiments were conducted on 42 rats of Krushinsky-Molodkina (K-M) line without adaptation to hypoxia and short-term adaptation to hypobaric hypoxia. Animals were intraperitoneally injected with sodium nitrite (0...
2016: Zhurnal Nevrologii i Psikhiatrii Imeni S.S. Korsakova
https://www.readbyqxmd.com/read/27899049/underreporting-of-complete-uterine-rupture-and-uterine-dehiscence-in-women-with-previous-cesarean-section
#15
Maria Fogelberg, Anton Baranov, Andreas Herbst, Olga Vikhareva
OBJECTIVE: To determine the true incidence of complete uterine rupture and uterine dehiscence among women delivered by cesarean section after a previous cesarean section. METHODS: Medical records of all women who delivered at University Hospital in Malmö, Sweden, during 2005-2009 (n = 21420) were retrieved from the electronic patient record system (EPRS). After adjustment for inaccuracies, 716 women who had undergone repeat cesarean section were identified and their operation reports were reviewed...
November 29, 2016: Journal of Maternal-fetal & Neonatal Medicine
https://www.readbyqxmd.com/read/27896685/the-interactions-of-vanadate-monomer-with-the-mycelium-of-fungus-phycomyces-blakesleeanus-reduction-or-uptake
#16
Mirzeta Hadžibrahimović, Desanka Sužnjević, Ferenc Pastor, Tijana Cvetić Antić, Milan Žižić, Joanna Zakrzewska, Miroslav Živić
The possibility of reduction of vanadate monomer in the mycelium of fungus Phycomyces blakesleeanus was investigated in this study by means of polarography. Control experiments were performed with vanadyl [V(IV)] and vanadate [V(V)] in 10 mM Hepes, pH 7.2. Addition of P. blakesleeanus mycelium resulted in disappearance of all V(IV) polarographic waves recorded in the control. This points to the uptake of all available V(IV) by the mycelium, up to 185 µmol/gFW, and suggests P. blakesleeanus as a potential agent in V(IV) bioremediation...
November 28, 2016: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/27895382/non-invasive-measurement-of-melanin-derived-radicals-in-living-mouse-tail-using-x-band-epr
#17
Yukihiro Ogawa, Megumi Ueno, Emiko Sekine-Suzuki, Ikuo Nakanishi, Ken-Ichiro Matsumoto, Shingo Fujisaki
The aim of this experiment is to measure in vivo generation of melanin-derived radicals non-invasively, as a quantifiable index of radio-biological effect. Melanin-derived radicals in a living intact mouse tail tip were non-invasively measured in very simple way using an X-band electron paramagnetic resonance spectrometer. Colored mouse strains, C57BL/6NCr, BDF1, and C3H/He, have clear EPR signal corresponding to melanin-derived radicals in the tail tip; however, albino mouse strains, BALB/cCr, ddY, ICR, have no EPR signals...
November 2016: Journal of Clinical Biochemistry and Nutrition
https://www.readbyqxmd.com/read/27889674/design-synthesis-characterization-and-cation-sensing-behavior-of-amino-naphthoquinone-receptor-selective-colorimetric-sensing-of-cu-ii-ion-in-nearly-aqueous-solution-with-mimicking-logic-gate-operation
#18
C Parthiban, Kuppanagounder P Elango
An amino-naphthoquione receptor (R1) has been rationally designed, synthesized and characterized using (1)H and (13)C NMR, LCMS and single crystal X-ray diffraction studies. The receptor exhibits an instantaneous colour change from yellow to blue selectively with Cu(II) ions in water-DMF (98:2% v/v) medium. The results of UV-Vis and fluorescence spectral studies indicates that the mechanism of sensing involves formation of a 1:1 complex between R1 and Cu(II) ion. The proposed mechanism has been confirmed through product analysis using FT-IR, UV-Vis, EPR and HRMS studies in addition to magnetic moment and elemental analysis measurements...
November 18, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/27889651/effect-of-rabi-splitting-on-the-low-temperature-electron-paramagnetic-resonance-signal-of-anthracite
#19
Ryhor Fedaruk, Roman Strzelczyk, Krzysztof Tadyszak, Siarhei A Markevich, Maria Aldona Augustyniak-Jabłokow
Specific distortions of the EPR signal of bulk anthracite are observed at low temperatures. They are accompanied by variations in the microwave oscillator frequency and are explained by the manifestation of the Rabi splitting due to the strong coupling between electron spins and the cavity, combined with the use of an automatic frequency-control (AFC) system. EPR signals are recorded at negligible saturation in the temperature range of 4-300K with use of the AFC system to keep the oscillator frequency locked to the resonant frequency of the TM110 cylinder cavity loaded with the sample...
November 19, 2016: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/27888840/nmr-solution-structure-determination-of-large-rna-protein-complexes
#20
REVIEW
Deepak Kumar Yadav, Peter J Lukavsky
Structure determination of RNA-protein complexes is essential for our understanding of the multiple layers of RNA-mediated posttranscriptional regulation of gene expression. Over the past 20years, NMR spectroscopy became a key tool for structural studies of RNA-protein interactions. Here, we review the progress being made in NMR structure determination of large ribonucleoprotein assemblies. We discuss approaches for the design of RNA-protein complexes for NMR structural studies, established and emerging isotope and segmental labeling schemes suitable for large RNPs and how to gain distance restraints from NOEs, PREs and EPR and orientational information from RDCs and SAXS/SANS in such systems...
November 2016: Progress in Nuclear Magnetic Resonance Spectroscopy
keyword
keyword
94905
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"