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https://www.readbyqxmd.com/read/29452159/cyp27a1-acts-on-the-pre-vitamin-d3-photoproduct-lumisterol-producing-biologically-active-hydroxy-metabolites
#1
Robert C Tuckey, Wei Li, Dejian Ma, Chloe Y S Cheng, Katie M Wang, Tae-Kang Kim, Saowanee Jeayeng, Andrzej T Slominski
Prolonged exposure of the skin to UV radiation causes previtamin D3, the initial photoproduct formed by opening of the B ring of 7-dehydrocholesterol, to undergo a second photochemical reaction where the B-ring is reformed giving lumisterol3 (L3), a stereoisomer of 7-dehydrocholesterol. L3 was believed to be an inactive photoproduct of excessive UV radiation whose formation prevents excessive vitamin D production. Recently, we reported that L3 is present in serum and that CYP11A1 can act on L3 producing monohydroxy- and dihydroxy-metabolites which inhibit skin cell proliferation similarly to 1α,25-dihydroxyvitamin D3...
February 13, 2018: Journal of Steroid Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/29452154/study-of-petrolatum-structure-explaining-its-variable-rheological-behavior
#2
A J P van Heugten, J Landman, A V Petukhov, H Vromans
The rheological properties of petrolatum are dependent on both temperature and thermal history. How this thermal dependency can be explained is unclear. In the past it has been suggested that the structure of petrolatum consists of a three-dimensional crystalline network. This has been established using old microscopic techniques only. Therefore a study on the microstructure of petrolatum was conducted using rheometry, DSC, pulsed NMR, polarized light microscopy and synchrotron X-ray. The combination of these techniques show that petrolatum is composed of 21% solid material at room temperature...
February 13, 2018: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/29451810/recent-developments-in-the-food-quality-detected-by-non-invasive-nuclear-magnetic-resonance-technology
#3
Kai Fan, Min Zhang
Nuclear magnetic resonance (NMR) is a rapid, accurate and non-invasive technology and widely used to detect the quality of food, particularly to fruits and vegetables, meat and aquatic products. This review is a survey of recent developments in experimental results for the quality of food on various NMR technologies in processing and storage over the past decade. Following a discussion of the quality discrimination and classification of food, analysis of food compositions and detection of physical, chemical, structural and microbiological properties of food are outlined...
February 16, 2018: Critical Reviews in Food Science and Nutrition
https://www.readbyqxmd.com/read/29451579/self-assembly-of-singlet-emitting-double-helical-silver-dimers-the-curious-coordination-chemistry-and-fluorescence-of-bisquinolylpyridone
#4
Charlotte M A Farrow, Geoffrey R Akien, Nathan R Halcovitch, James A Platts, M P Coogan
2,6-Bis(2-quinolyl)-4(1H)-pyridone 1, a novel quinoline analogue of the well-known ligand 2-terpyridone, shows unusual fluorescence with a large Stokes shift and low energy emission. Pyridine-pyridone tautomerism is investigated by NMR and theoretical methods and indicates that the low energy emission is from the pyridine form. 1 reacts with Ag(i) salts to give a double helical Ag 2 N 6 core showing a BLUE shift in fluorescence with respect to the free ligand, which has been characterised experimentally and theoretically as involving an unusual mixed MLCT/ILCT excited state and emission from a singlet state...
February 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29451338/can-dimedone-be-used-to-study-selenoproteins-an-investigation-into-the-reactivity-of-dimedone-towards-oxidized-forms-of-selenocysteine
#5
N Connor Payne, Drew R Barber, Erik L Ruggles, Robert J Hondal
Dimedone is a widely used reagent to assess the redox state of cysteine-containing proteins as it will alkylate sulfenic acid residues, but not sulfinic acid residues. While it has been reported that dimedone can label selenenic acid residues in selenoproteins, we investigated the stability, and reversibility of this label in a model peptide system. We also wondered whether dimedone could be used to detect seleninic acid residues. We used benzenesulfinic acid, benzeneseleninic acid, and model selenocysteine-containing peptides to investigate possible reactions with dimedone...
February 16, 2018: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/29451336/electronically-unsaturated-three-coordinated-aluminum-hydride-and-organoaluminum-cations
#6
Billa Prashanth, Mamta Bhandari, Satyam Ravi, K R Shamasundar, Sanjay Singh
New three coordinated and electronically unsaturated aluminum hydride [LAlH]+[HB(C6F5)3]- and aluminum methyl [LAlMe]+[MeB(C6F5)3]- cations have been prepared. The quantitative estimation of Lewis acidity by Gutmann-Beckett method reveals [LAlH]+[HB(C6F5)3]- to be better Lewis acid than B(C6F5)3 and AlCl3 making these compounds ideal catalysts for Lewis acid mediated reactions. To highlight that the work is of fundamental importance, catalytic hydroboration of aliphatic and aromatic aldehydes and ketones have been demonstrated...
February 16, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29451289/multi-molecular-emission-of-a-cationic-pt-ii-complex-through-hydrogen-bonding-interactions
#7
Kaho Yamaguchi, Kazuma Yamawaki, Takuya Kimura, Junpei Kuwabara, Takeshi Yasuda, Yoshinobu Nishimura, Takaki Kanbara
The cationic Pt complexes with amide groups have been found to show dimer emission through hydrogen bonding interactions with counter anions even at low concentration. In order to investigate further details of dimer emission, we prepared three Pt complexes, Pt·B(C6F5)4, Pt·Cl, and Pt·PF6, whose counter anions possess different strengths of a hydrogen bonding acceptor. Hydrogen bonding interactions in the ground state and excited-state dynamics of the Pt complexes were evaluated by NMR analysis, temperature dependence, and kinetics of dimer emission...
February 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29451283/a-chemo-and-regiocontrolled-approach-to-bipyrazoles-and-pyridones-via-the-reaction-of-ethyl-5-acyl-4-pyrone-2-carboxylates-with-hydrazines
#8
D L Obydennov, L R Khammatova, O S Eltsov, V Y Sosnovskikh
Chemo- and regiocontrolled syntheses of pyrazoles and pyridones are presented on the basis of 4-pyrones. A novel approach towards highly functionalized 3,4'-bipyrazoles has been developed by using reactions of ethyl 5-acylcomanoates with hydrazines. The acid-promoted double cyclocondensation allows switching of the structure of the pyrazole rings easily through changing both the nature of hydrazine and the reaction conditions. The transformation of 4-pyrones with phenylhydrazine in EtOH at -20 °C leads to hydroxypyridones as monoaddition products which can be used as precursors for the preparation of pyridone and pyrazole derivatives...
February 16, 2018: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/29450991/mass-spectrometry-based-fast-photochemical-oxidation-of-proteins-fpop-for-higher-order-structure-characterization
#9
Ke Sherry Li, Liuqing Shi, Michael L Gross
Assessment of protein structure and interaction is crucial for understanding protein structure/function relationships. Compared to high-resolution structural tools, including X-ray crystallography, nuclear magnetic resonance (NMR), and cryo-EM, and traditional low-resolution methods, such as circular dichroism, UV-vis, and florescence spectroscopy, mass spectrometry (MS)-based protein footprinting affords medium-to-high resolution (i.e., regional and residue-specific insights) by taking advantage of proteomics methods focused on the primary structure...
February 16, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29450931/sulfur-radical-transfer-and-coupling-reaction-to-benzoxazine-groups-a-new-reaction-route-for-preparation-of-polymeric-materials-using-elemental-sulfur-as-a-feedstock
#10
Ho-Keng Lin, Ying-Ling Liu
A novel approach to preparing polymeric materials using elemental sulfur as a feedstock through the newly developed sulfur radical transfer and coupling (SRTC) reaction is reported herein. Polybenzoxazines with high sulfur contents are prepared using the SRTC reaction with benzoxazine compounds as the radical acceptors. The reactions between elemental sulfur and benzoxazine rings are analyzed with Fourier transform infrared (FTIR), 1 H NMR, and 13 C DEPT spectroscopies to elucidate the SRTC reaction mechanism...
February 16, 2018: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/29450824/solid-state-13-c-15-n-nmr-resonance-assignment-of-hepatitis-b-virus-core-protein
#11
Lauriane Lecoq, Shishan Wang, Thomas Wiegand, Stéphane Bressanelli, Michael Nassal, Beat H Meier, Anja Böckmann
Each year, nearly 900,000 deaths are due to serious liver diseases caused by chronic hepatitis B virus infection. The viral particle is composed of an outer envelope and an inner icosahedral nucleocapsid formed by multiple dimers of a ~ 20 kDa self-assembling core protein (Cp). Here we report the solid-state 13 C and 15 N resonance assignments of the assembly domain, Cp149, of the core protein in its capsid form. A secondary chemical shift analysis of the 140 visible residues suggests an overall alpha-helical three-dimensional fold matching that derived for Cp149 from the X-ray crystallography of the capsid, and from solution-state NMR of the Cp149 dimer...
February 16, 2018: Biomolecular NMR Assignments
https://www.readbyqxmd.com/read/29450823/nmr-resonance-assignments-of-rnase-p-protein-from-thermotoga-maritima
#12
Danyun Zeng, Benjamin P Brown, Markus W Voehler, Sheng Cai, Nicholas J Reiter
Ribonuclase P (RNase P) is an essential metallo-endonuclease that catalyzes 5' precursor-tRNA (ptRNA) processing and exists as an RNA-based enzyme in bacteria, archaea, and eukaryotes. In bacteria, a large catalytic RNA and a small protein component assemble to recognize and accurately cleave ptRNA and tRNA-like molecular scaffolds. Substrate recognition of ptRNA by bacterial RNase P requires RNA-RNA shape complementarity, intermolecular base pairing, and a dynamic protein-ptRNA binding interface. To gain insight into the binding specificity and dynamics of the bacterial protein-ptRNA interface, we report the backbone and side chain 1 H, 13 C, and 15 N resonance assignments of the hyperthermophilic Thermatoga maritima RNase P protein in solution at 318 K...
February 15, 2018: Biomolecular NMR Assignments
https://www.readbyqxmd.com/read/29450422/remarkable-structural-effects-on-the-complexation-of-actinides-with-h-phosphonates-a-combined-experimental-and-quantum-chemical-study
#13
Aditi Chandrasekar, Brahmmananda Rao C V S, Mahesh Sundararajan, Tapan K Ghanty, N Sivaraman
The structural effects of the carbon chain on the extraction of actinides by organo-phosphorus extractants have been examined experimentally and by computation. Branched butyl H-phosphonates and their linear chain isomer, n-butyl H-phosphonate (DBHP), were synthesised and characterised using IR, NMR and GC-MS techniques. Their physical properties viz. viscosity, density and aqueous solubility have been examined. DBHP, Di-iso-butyl H phosphonate (DiBHP) and Di-sec-butyl H phosphonate (DsBHP) were employed for the extraction of uranium and americium ions from nitric acid...
February 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29450418/distinct-photophysical-behaviour-and-transport-of-cell-impermeable-ru-bpy-2-dppz-2-in-live-cells-using-cucurbit-7-uril-as-a-delivery-system
#14
Meenakshi N Shinde, Soniya S Rao, Shridhar P Gejji, Anupa A Kumbhar
Here, we report the delivery of a cell-impermeable [Ru(bpy) 2 dppz] 2+ complex across a cell membrane using a cucurbit[7]uril molecular container. Encapsulation of complex 1 in the cucurbit[7]uril cavity showed an 830-fold enhancement in the luminescence intensity of the non-emissive complex in aqueous solution. This molecular light-switch effect stems from the incorporation of the dppz ligand of 1 inside the CB7 cavity and can be attributed to long range coulombic forces between Ru 2+ and the carbonyl portal of CB7 via CHO interactions...
February 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29449636/structural-elucidation-of-a-polysaccharide-from-flammulina-velutipes-and-its-immunomodulation-activities-on-mouse-b-lymphocytes
#15
Wen-Han Wang, Jing-Song Zhang, Ting Feng, Jing Deng, Chi-Chung Lin, Hua Fan, Wen-Juan Yu, Hai-Ying Bao, Wei Jia
A novel polysaccharide FVPB2 was purified from fruiting bodies of Flammulina velutipes. Its structure was elucidated by monosaccharide composition and methylation analyses, UV-Visible and FTIR spectroscopy as well as NMR. FVPB2 was a homogeneous heteropolysaccharide (molecular weight ~ 1.50 × 10 4 Da) containing D-galactose, D-mannose, L-fucose, and D-glucose at molar ratio of 1.9:1.2:1:2.5. In vitro immunomodulatory studies showed FVPB2 induced proliferation of mouse spleen lymphocytes in a dose-dependent manner...
February 15, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29449376/structural-basis-for-the-glycosyltransferase-activity-of-the-salmonella-effector-ssek3
#16
Diego Esposito, Regina A Günster, Luigi Martino, Kamel El Omari, Armin Wagner, Teresa L M Thurston, Katrin Rittinger
The Salmonella secreted effector SseK3 translocates into host cells, targeting innate immune responses including NF-κB activation. SseK3 is a glycosyltransferase that transfers an N-acetylglucosamine (GlcNAc) moiety onto the guanidino group of a target arginine, modulating host cell function. However, a lack of structural information has precluded elucidation of the molecular mechanisms in arginine and GlcNAc selection. We report here the crystal structure of SseK3 in its apo form and in complex with hydrolysed UDP-GlcNAc...
February 15, 2018: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29449323/structural-basis-of-sirna-recognition-by-trbp-double-stranded-rna-binding-domains
#17
Gregoire Masliah, Christophe Maris, Sebastian Lb König, Maxim Yulikov, Florian Aeschimann, Anna L Malinowska, Julie Mabille, Jan Weiler, Andrea Holla, Juerg Hunziker, Nicole Meisner-Kober, Benjamin Schuler, Gunnar Jeschke, Frederic H-T Allain
The accurate cleavage of pre-micro(mi)RNAs by Dicer and mi/siRNA guide strand selection are important steps in forming the RNA-induced silencing complex (RISC). The role of Dicer binding partner TRBP in these processes remains poorly understood. Here, we solved the solution structure of the two N-terminal dsRNA binding domains (dsRBDs) of TRBP in complex with a functionally asymmetric siRNA using NMR, EPR, and single-molecule spectroscopy. We find that siRNA recognition by the dsRBDs is not sequence-specific but rather depends on the RNA shape...
February 15, 2018: EMBO Journal
https://www.readbyqxmd.com/read/29448823/chemical-constituents-of-genista-numidica-spach-aerial-parts-and-their-antimicrobial-antioxidant-and-antityrosinase-activities
#18
Naima Boutaghane, Abdulmagid Alabdul Magid, Amin Abedini, Anaïs Cafolla, Hanène Djeghim, Sophie C Gangloff, Laurence Voutquenne-Nazabadioko, Zahia Kabouche
A previously undescribed triterpenoid saponin, 3-O-[α-l-rhamnopyranosyl-(1→2)-{β-d-glucopyranosyl-(1→6)-}β-d-galactopyranosyl-(1→2)-β-d-glucuronopyranosyl]-sophoradiol (1), in addition to twenty-nine known constituents (2-30) were isolated from the aerial parts of Genista numidica Spach. Structures elucidation was performed by comprehensive 1D- and 2D-NMR analyses and HRESIMS. The extracts, fractions and isolated compounds were evaluated for their antibacterial, antioxidant and tyrosinase inhibitory activities...
February 15, 2018: Natural Product Research
https://www.readbyqxmd.com/read/29448760/identification-of-new-compounds-from-sage-flowers-salvia-officinalis-l-as-markers-for-quality-control-and-the-influence-of-the-manufacturing-technology-on-the-chemical-composition-and-antibacterial-activity-of-sage-flower-extracts
#19
Sebastian Gericke, Tilo Lübken, Diana Wolf, Martin Kaiser, Christian Hannig, Karl Speer
Parts of Salvia species such as its flowers and leaves are currently used as a culinary herb and for some medicinal applications. To distinguish the different sage extracts it is necessary to analyze their individual chemical compositions. Their characteristic compounds might be established as markers to differentiate between sage flowers and leaf extracts or to determine the manufacturing technology and storage conditions. Tri-p-coumaroylspermidine can be detected only in flowers and has been described here for Salvia and Lavandula species for the first time...
February 16, 2018: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/29448615/synthesis-of-the-molybdenum-precursor-for-slurry-phase-hydrocracking-of-heavy-oil
#20
Byong-Min Choi, Seok-Hwan Son, Min-Sub Noh, Kwang-Seok Lee, Chul-Wee Lee, Sun-Yeong Park, Min-Chul Chung
In this study, Molybdenum precursors were synthesized with butanoic acid, hexanoic acid, nonanoic acid, decanoic acid, and undecanoic acid. In order to determine chemical structure of Synthesized molybdenum precursors, 1H(13C)-NMR, EA and ICP were used pyrolysis properties were measured TGA. The molybdenum precursors was used for Hydrocracking of Vacuum R1esidue (VR). It was shown that molybdenum nonanoate(3) was shown the lowerst Toluene Insoluble and Gas Product about 2.1 and 5.0 percent.
February 1, 2018: Journal of Nanoscience and Nanotechnology
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