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https://www.readbyqxmd.com/read/28636347/the-structure-and-dynamics-of-alginate-gels-crosslinked-by-polyvalent-ions-probed-via-solid-state-nmr-spectroscopy
#1
Jiří Brus, Martina Urbanová, Jiri Czernek, Miroslava Pavelkova, Katerina Kubova, Jakub Vyslouzil, Sabina Abbrent, Rafal Konefal, Jiri Horsky, David Vetchy, Jan Vysloužil, Pavel Kulich
Alginate gels are an outstanding biomaterial widely applicable in tissue engineering, medicine, and pharmacy for cell transplantation, wound healing and efficient bioactive agent delivery, respectively. This contribution provides new and comprehensive insight into the atomic-resolution structure and dynamics of polyvalent ion-crosslinked alginate gels in microbead formulations. By applying various advanced solid-state NMR (ssNMR) spectroscopy techniques, we verified the homogenous distribution of the crosslinking ions in the alginate gels and the high degree of ion exchange...
June 21, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28636046/lead-ii-soaps-crystal-structures-polymorphism-and-solid-and-liquid-mesophases
#2
F J Martínez-Casado, M Ramos-Riesco, J A Rodríguez-Cheda, M I Redondo-Yélamos, L Garrido, A Fernández-Martínez, J García-Barriocanal, I da Silva, M Durán-Olivencia, A Poulain
The long-chain members of the lead(ii) alkanoate series or soaps, from octanoate to octadecanoate, have been thoroughly characterized by means of XRD, PDF analysis, DSC, FTIR, ssNMR and other techniques, in all their phases and mesophases. The crystal structures at room temperature of all of the members of the series are now solved, showing the existence of two polymorphic forms in the room temperature crystal phase, different to short and long-chain members. Only nonanoate and decanoate present both forms, and this polymorphism is proven to be monotropic...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28629063/substitution-of-strontium-and-boron-into-hydroxyapatite-crystals-effect-on-physicochemical-properties-and-biocompatibility-with-human-wharton-jelly-stem-cells
#3
Joanna Kolmas, Frédéric Velard, Aneta Jaguszewska, Flora Lemaire, Halima Kerdjoudj, Sophie C Gangloff, Agnieszka Kaflak
Hydroxyapatite (HA) enriched with strontium and boron ions was synthesized using two different methods: the precipitation method (Sr,B-HAw) and the dry method (Sr,B-HAd). Additionally, for the sake of comparison, the "pure" unsubstituted HA was prepared together with HAs substituted only with one type of a foreign ion. The obtained materials were subjected to physicochemical analysis with the use of various analytical methods, such as powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectroscopy (ICP-OES), Fourier transform infrared spectroscopy (FT-IR) and solid-state proton nuclear magnetic resonance ((1)H ssNMR)...
October 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28623473/increasing-the-bile-acid-sequestration-performance-of-cationic-hydrogels-by-using-an-advanced-controlled-polymerization-technique
#4
Patrícia V Mendonça, André Matos, Andreia F Sousa, Arménio C Serra, Sérgio Simões, Jorge F J Coelho
PURPOSE: To investigate the influence of the polymerization technique and the content of hydroxyl groups on the performance of new bile acid sequestrants based on PAMPMTA-co-PHEA (PAMPTMA: poly((3-acrylamidopropyl)trimethylammonium chloride); PHEA: poly(2-hydroxyethyl acrylate)) hydrogels. METHODS: PAMPMTA-co-PHEA hydrogels were prepared using either free radical polymerization or supplemental activator and reducing agent atom transfer radical polymerization. The chemical structure and composition of the hydrogels was confirmed by both FTIR and ssNMR...
June 16, 2017: Pharmaceutical Research
https://www.readbyqxmd.com/read/28621371/does-z-equal-1-or-2-enhanced-powder-nmr-crystallography-verification-of-a-disordered-room-temperature-crystal-structure-of-a-p38-inhibitor-for-chronic-obstructive-pulmonary-disease
#5
Cory M Widdifield, Sten O Nilsson Lill, Anders Broo, Maria Lindkvist, Anna Pettersen, Anna Svensk Ankarberg, Peter Aldred, Staffan Schantz, Lyndon Emsley
The crystal structure of the Form A polymorph of N-cyclopropyl-3-fluoro-4-methyl-5-[3-[[1-[2-[2-(methylamino)ethoxy]phenyl]cyclopropyl]amino]-2-oxo-pyrazin-1-yl]benzamide (i.e., AZD7624), determined using single-crystal X-ray diffraction (scXRD) at 100 K, contains two molecules in the asymmetric unit (Z' = 2) and has regions of local static disorder. This substance has been in phase IIa drug development trials for the treatment of chronic obstructive pulmonary disease, a disease which affects over 300 million people and contributes to nearly 3 million deaths annually...
June 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28613900/solid-state-nmr-provides-evidence-for-small-amplitude-slow-domain-motions-in-a-multi-spanning-transmembrane-%C3%AE-helical-protein
#6
Daryl Good, Charlie Pham, Jacob Jagas, Józef R Lewandowski, Vladimir Ladizhansky
Proteins are dynamic entities and populate ensembles of conformations. Transitions between states within a conformational ensemble occur over a broad spectrum of amplitude and time scales, and are often related to biological function. Whereas solid-state NMR (SSNMR) spectroscopy has recently been used to characterize conformational ensembles of proteins in the microcrystalline states, its applications to membrane proteins remain limited. Here we use SSNMR to study conformational dynamics of a seven-helical transmembrane (TM) protein, Anabaena Sensory Rhodopsin (ASR) reconstituted in lipids...
June 14, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28572641/application-of-nuclear-magnetic-resonance-spectroscopy-in-food-adulteration-determination-the-example-of-sudan-dye-i-in-paprika-powder
#7
Yaxi Hu, Shuo Wang, Shenlin Wang, Xiaonan Lu
Carcinogenic Sudan I has been added illegally into spices for an apparent freshness. (1)H solution and solid-state (SS) nuclear magnetic resonance (NMR) spectroscopies were applied and compared for determination of Sudan I in paprika powders (PPs). For solution NMR, PPs spiked with Sudan I were extracted with acetonitrile, centrifuged, rotor-evaporated, and re-dissolved in DMSO-d6 for spectral collection. For SSNMR, Sudan I contaminated PPs were mixed with DMSO-d6 solution and used for spectral collection. Linear regression models constructed for quantitative analyses resulted in the average accuracies for unknown samples as 98% and 105%, respectively...
June 1, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28560567/gd-3-chelated-lipid-accelerates-solid-state-nmr-spectroscopy-of-seven-transmembrane-proteins
#8
Chang Liu, Jing Liu, Xiaojun Xu, ShengQi Xiang, Shenlin Wang
Solid-state NMR (SSNMR) is an attractive technique for studying large membrane proteins in membrane-mimetic environments. However, SSNMR experiments often suffer from low efficiency, due to the inherent low sensitivity and the long recycle delays needed to recover the magnetization. Here we demonstrate that the incorporation of a small amount of a Gd(3+)-chelated lipid, Gd(3+)-DMPE-DTPA, into proteoliposomes greatly shortens the spin-lattice relaxation time ((1)H-T 1) of lipid-reconstituted membrane proteins and accelerates the data collection...
May 30, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28548827/dynamic-disorder-and-electronic-structures-of-electron-precise-dianionic-diboranes-insights-from-solid-state-multinuclear-magnetic-resonance-spectroscopy
#9
Y T Angel Wong, Johannes Landmann, Maik Finze, David L Bryce
The J((11)B,(11)B) coupling constants of various salts of the electron-precise hexacyanodiborane(6) dianion, [B2(CN)6](2-), were obtained using (11)B double-quantum-filtered (DQF) J-resolved solid-state nuclear magnetic resonance (SSNMR) spectroscopy. Our results show that the magnitude of the DQF J splitting is influenced by both the crystallographic symmetry of the system and the presence of dynamics. The splittings are amplified by a factor of 3 as compared to the corresponding theoretical J coupling constants for cases where (1) there is an absence of dynamics but the boron pairs are crystallographically equivalent or (2) the boron pairs are crystallographically inequivalent but are rendered magnetically equivalent on the time scale of the experiment due to dynamic disorder, which was identified by (11)B and (13)C SSNMR experiments...
June 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28535056/solid-state-nmr-structure-based-inhibitor-design-to-achieve-selective-inhibition-of-the-parallel-in-register-%C3%AE-sheet-versus-antiparallel-iowa-mutant-%C3%AE-amyloid-fibrils
#10
Qinghui Cheng, Wei Qiang
Solid-state nuclear magnetic resonance (ssNMR) spectroscopy has been widely applied to characterize the high-resolution structures of β-amyloid (Aβ) fibrils. While these structures provide crucial molecular insights on the deposition of amyloid plaques in Alzheimer's diseases (AD), ssNMR structures have been rarely used so far as the basis for designing inhibitors. It remains a challenge because the ssNMR-based Aβ fibril structures were usually obtained with sparsely isotope-labeled peptides with limited experimental constraints, where the structural models, especially the side-chain coordinates, showed restricted precision...
May 30, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28511991/calculation-of-the-cross-sectional-shape-of-a-fibril-from-equatorial-scattering
#11
Biel Roig-Solvas, Lee Makowski
An alternate formulation of helical diffraction theory is used to generate cross-sectional shapes of fibrous structures from equatorial scattering. We demonstrate this approach with computationally generated scattering intensities and then apply it to scattering data from Tobacco Mosaic Virus (TMV) and in vitro assembled fibrils of Aβ40 peptides. Refining the cross-sectional shape of TMV from SAXS data collected on a 26mg/ml solution resulted in a circular shape with outer diameter of ∼180Å and inner diameter of ∼40Å consistent with the known structure of TMV...
May 13, 2017: Journal of Structural Biology
https://www.readbyqxmd.com/read/28501588/oligomeric-structure-of-anabaena-sensory-rhodopsin-in-a-lipid-bilayer-environment-by-combining-solid-state-nmr-and-long-range-deer-constraints
#12
Sergey Milikisiyants, Shenlin Wang, Rachel A Munro, Matthew Donohue, Meaghan E Ward, David Bolton, Leonid S Brown, Tatyana I Smirnova, Vladimir Ladizhansky, Alex I Smirnov
Oligomerization of membrane proteins is common in nature. Here, we combine spin-labeling double electron-electron resonance (DEER) and solid-state NMR (ssNMR) spectroscopy to refine the structure of an oligomeric integral membrane protein, Anabaena sensory rhodopsin (ASR), reconstituted in a lipid environment. An essential feature of such a combined approach is that it provides structural distance restraints spanning a range of ca 3-60Å while using the same sample preparation (i.e., mutations, paramagnetic labeling, and reconstitution in lipid bilayers) for both ssNMR and DEER...
May 10, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28480926/confinement-effects-of-a-crystalline-sponge-on-ferrocene-and-ferrocene-carboxaldehyde
#13
Gabriel Brunet, Damir A Safin, Koen Robeyns, Glenn A Facey, Ilia Korobkov, Yaroslav Filinchuk, Muralee Murugesu
The pivotal role of ππ interactions in the inclusion behaviour of a series of organometallic sandwich compounds is studied through single-crystal X-ray diffraction. The confinement effects of a crystalline sponge host are investigated where, notably, we observe an enhanced rotation of the ligand ring once encapsulated by the nanoporous framework, as evidenced by SSNMR experiments.
May 8, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28471174/investigating-sodium-storage-mechanisms-in-tin-anodes-a-combined-pair-distribution-function-analysis-density-functional-theory-and-solid-state-nmr-approach
#14
Joshua M Stratford, Martin Mayo, Phoebe K Allan, Oliver Pecher, Olaf J Borkiewicz, Kamila M Wiaderek, Karena W Chapman, Chris J Pickard, Andrew J Morris, Clare P Grey
The alloying mechanism of high-capacity tin anodes for sodium-ion batteries is investigated using a combined theoretical and experimental approach. Ab initio random structure searching (AIRSS) and high-throughput screening using a species-swap method provide insights into a range of possible sodium-tin structures. These structures are linked to experiments using both average and local structure probes in the form of operando pair distribution function analysis, X-ray diffraction, and (23)Na solid-state nuclear magnetic resonance (ssNMR), along with ex situ (119)Sn ssNMR...
May 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28455777/insights-into-nano-and-micron-scale-phase-separation-in-amorphous-solid-dispersions-using-fluorescence-based-techniques-in-combination-with-solid-state-nuclear-magnetic-resonance-spectroscopy
#15
Hitesh S Purohit, James D Ormes, Sugandha Saboo, Yongchao Su, Matthew S Lamm, Amanda K P Mann, Lynne S Taylor
PURPOSE: Miscibility between the drug and the polymer in an amorphous solid dispersion (ASD) is considered to be one of the most important factors impacting the solid state stability and dissolution performance of the active pharmaceutical ingredient (API). The research described herein utilizes emerging fluorescence-based methodologies to probe (im)miscibility of itraconazole (ITZ)-hydroxypropyl methylcellulose (HPMC) ASDs. METHODS: The ASDs were prepared by solvent evaporation with varying evaporation rates and were characterized by steady-state fluorescence spectroscopy, confocal imaging, differential scanning calorimetry (DSC), and solid state nuclear magnetic resonance (ssNMR) spectroscopy...
April 28, 2017: Pharmaceutical Research
https://www.readbyqxmd.com/read/28402625/interplay-of-internal-structure-and-interfaces-on-the-emitting-properties-of-hybrid-zno-hierarchical-particles
#16
Monica Distaso, Giovanni Bertoni, Stefano Todisco, Sergio Marras, Vito Gallo, Liberato Manna, Wolfgang Peukert
The design of hybrid organic/inorganic nanostructures with controlled assembly drives the development of materials with new or improved properties and superior performances. In this paper, the surface and internal structure of hybrid ZnO poly-N-vinylpyrrolidone (ZnO/PVP) mesocrystals are investigated in detail and correlated with their emitting properties. A photoluminescence study at room temperature reveals that the as-synthesized particles show a remarkable ultraviolet (UV) emission, whereas an emission from defects in the visible region is not observed...
April 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28368030/co-grinding-effect-on-crystalline-zaltoprofen-with-%C3%AE-cyclodextrin-cucurbit-7-uril-in-tablet-formulation
#17
Shanshan Li, Xiang Lin, Kailin Xu, Jiawei He, Hongqin Yang, Hui Li
This work aimed to investigate the co-grinding effects of β-cyclodextrin (β-CD) and cucurbit[7]uril (CB[7]) on crystalline zaltoprofen (ZPF) in tablet formulation. Crystalline ZPF was prepared through anti-solvent recrystallization and fully analyzed through single-crystal X-ray diffraction. Co-ground dispersions and mono-ground ZPF were prepared using a ball grinding process. Results revealed that mono-ground ZPF slightly affected the solid state, solubility, and dissolution of crystalline ZPF. Co-ground dispersions exhibited completely amorphous states and elicited a significant reinforcing effect on drug solubility...
April 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28353338/proton-based-ultrafast-magic-angle-spinning-solid-state-nmr-spectroscopy
#18
Rongchun Zhang, Kamal H Mroue, Ayyalusamy Ramamoorthy
Protons are vastly abundant in a wide range of exciting macromolecules and thus can be a powerful probe to investigate the structure and dynamics at atomic resolution using solid-state NMR (ssNMR) spectroscopy. Unfortunately, the high signal sensitivity, afforded by the high natural-abundance and high gyromagnetic ratio of protons, is greatly compromised by severe line broadening due to the very strong (1)H-(1)H dipolar couplings. As a result, protons are rarely used, in spite of the desperate need for enhancing the sensitivity of ssNMR to study a variety of systems that are not amenable for high resolution investigation using other techniques including X-ray crystallography, cryo-electron microscopy, and solution NMR spectroscopy...
March 29, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28315762/bionanocomposite-films-based-on-polysaccharides-from-banana-peels
#19
Túlio Ítalo S Oliveira, Morsyleide F Rosa, Michael J Ridout, Kathryn Cross, Edy S Brito, Lorena M A Silva, Selma E Mazzetto, Keith W Waldron, Henriette M C Azeredo
Pectin and cellulose nanocrystals (CNCs) isolated from banana peels were used to prepare films. The effects of a reinforcing phase (CNCs) and a crosslinker (citric acid, CA) on properties of pectin films were studied. Glycerol-plasticized films were prepared by casting, with different CNC contents (0-10wt%), with or without CA. Overall tensile properties were improved by intermediate CNC contents (around 5wt%). The water resistance and water vapor barrier properties were also enhanced by CNC. Evidences were found from Fourier Transform Infrared (FTIR) spectra supporting the occurrence of crosslinking by CA...
August 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28277547/backbone-assignment-of-perdeuterated-proteins-by-solid-state-nmr-using-proton-detection-and-ultrafast-magic-angle-spinning
#20
Pascal Fricke, Veniamin Chevelkov, Maximilian Zinke, Karin Giller, Stefan Becker, Adam Lange
Solid-state NMR (ssNMR) is a technique that allows the study of protein structure and dynamics at atomic detail. In contrast to X-ray crystallography and cryo-electron microscopy, proteins can be studied under physiological conditions-for example, in a lipid bilayer and at room temperature (0-35 °C). However, ssNMR requires considerable amounts (milligram quantities) of isotopically labeled samples. In recent years, (1)H-detection of perdeuterated protein samples has been proposed as a method of alleviating the sensitivity issue...
April 2017: Nature Protocols
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