Read by QxMD icon Read


Zhengrong Yang, Qingxian Zhou, Leo Mok, Anukriti Singh, Douglas J Swartz, Ina L Urbatsch, Christie G Brouillette
Structural changes in mouse P-glycoprotein (Pgp) induced by thermal unfolding were studied by differential scanning calorimetry (DSC), circular dichroism and fluorescence spectroscopy to gain insight into the solution conformation(s) of this ABC transporter that may not be apparent from current crystal structures. DSC of reconstituted Pgp showed two thermal unfolding transitions in the absence of MgATP, suggesting that each transition involved the cooperative unfolding of two or more interacting structural domains...
October 23, 2016: Biochimica et Biophysica Acta
Mayte Conejero-Muriel, Isaac Rodriguez-Ruiz, Cristobal Verdugo-Escamilla, Andreu Llobera, Jose Antonio Gavira
Microfluidics or lab-on-a-chip technology offer clear advantages over conventional systems such as a dramatic reduction of reagent consumption or a shorter analysis time, which are translated into costs effective systems. In this work, we present a photonic enzymatic lab on a chip reactor based on Cross-Linked Enzyme Crystals (CLECs), able to work in continuous flow, as a highly sensitive, robust, reusable and stable platform for continuous sensing with superior performance as compared to the state of the art...
October 26, 2016: Analytical Chemistry
Sebastian Hasenstab-Riedel, Lisa Mann, Patrick Voßnacker, Carsten Müller
Tetramethylammonium tetraiodopentabromide [NMe4][I4Br5] was the first iodobromide synthesized and crystallized in an ionic liquid as well as in dichloromethane. The new iodobro-mides show different structure motives yet unknown from other nonahalides and can be better described as [(I2Br3)- · 2IBr]. The additional IBr units are connected by halogen-halogen interactions on the central V-shaped [I2Br3]-. The characterization was performed by Raman spectroscopy and single crystal X-ray structure determi-nation...
October 26, 2016: Chemistry: a European Journal
Shmuel Willensky, Hagit Bar-Rogovsky, Eduardo A Bignon, Nicole D Tischler, Yorgo Modis, Moshe Dessau
Hantaviruses are important emerging human pathogens and are the causative agents of serious diseases in humans with high mortality rates. Like other members in the Bunyaviridae family their M segment encodes two glycoproteins, GN and GC, which are responsible for the early events of infection. Hantaviruses deliver their tripartite genome into the cytoplasm by fusion of the viral and endosomal membranes in response to the reduced pH of the endosome. Unlike phleboviruses (e.g. Rift valley fever virus), that have an icosahedral glycoprotein envelope, hantaviruses display a pleomorphic virion morphology as GN and GC assemble into spikes with apparent four-fold symmetry organized in a grid-like pattern on the viral membrane...
October 2016: PLoS Pathogens
Tongtong Tian, Qiongzheng Hu, Yi Wang, Yanan Gao, Li Yu
A series of imidazolium-based surface active ionic liquids (IM-SAILs), viz. single-chained IM-SAILs, 1-alkyl-3-methylimidazolium bromide ([Cnmim]Br, n=12, 14, 16), 1-dodecyl-3-methylimidazolium salicylate ([C12mim]Sal), 1-dodecyl-3-methylimidazolium 3-hydroxy-2-naphthoate ([C12mim]HNC), 1-dodecyl-3-methylimidazolium cinnamate ([C12mim]CA), 1-dodecyl-3-methylimidazolium para-hydroxy-cinnamate ([C12mim]PCA); gemini IM-SAIL, 1,2-bis(3-dodecylimidazolium-1-yl) ethane bromide ([C12-2-C12im]Br2), along with three short-chained ionic liquids (ILs), ethylammonium nitrate (EAN), propylammonium nitrate (PAN) and butylammonium nitrate (BAN), were synthesized and applied to nematic liquid crystal (LC)-fluid interfaces...
October 26, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Travis S Hughes, Jinsai Shang, Richard Brust, Ian Mitchelle S de Vera, Jakob Fuhrmann, Claudia Ruiz, Michael D Cameron, Theodore M Kamenecka, Douglas J Kojetin
In a previous study, a co-crystal structure of PPARγ bound to 2-chloro-N-(3-chloro-4-((5-chlorobenzo[d]thiazol-2-yl)thio)phenyl)-4-(trifluoromethyl)benzenesulfonamide (1, T2384) revealed two orthosteric pocket binding modes attributed to a concentration-dependent biochemical activity profile. However, 1 also bound an alternate/allosteric site that could alternatively account for the profile. Here, we show ligand aggregation afflicts the activity profile of 1 in biochemical assays. However, ligand-observed fluorine (19F) and protein-observed NMR confirms 1 binds PPARγ with two orthosteric binding modes and an allosteric site...
October 26, 2016: Journal of Medicinal Chemistry
Omer Kirshenboim, Sebastian Kozuch
Halogen bonds (XB) are no longer newcomers in the chemistry family. However, XB in hypervalent halogens has not been thoroughly studied. We provide a molecular orbital explanation of the shape and strength of XBs in hypervalent halogens and other species, focusing on the charge transfer and electrostatic aspects of these bonds. Our results show that σ-holes (and subsequently the XBs associated with them) can be easily divided and bent by the influence of equatorial substituents. Inductive effect of both the equatorial and axial groups can affect these distortions, but also the angle between the equatorial ligands has a large influence on the shape of the σ-holes and the molecular orbitals acting as electron acceptor...
October 26, 2016: Journal of Physical Chemistry. A
Eileen K Jaffe
Porphobilinogen synthase (PBGS), also known as 5-aminolevulinate dehydratase, is an essential enzyme in the biosynthesis of all tetrapyrroles, which function in respiration, photosynthesis, and methanogenesis. Throughout evolution, PBGS adapted to a diversity of cellular niches and evolved to use an unusual variety of metal ions both for catalytic function and to control protein multimerization. With regard to the active site, some PBGSs require Zn(2+); a subset of those, including human PBGS, contain a constellation of cysteine residues that acts as a sink for the environmental toxin Pb(2+)...
October 26, 2016: Accounts of Chemical Research
Ethan P McMoran, Douglas R Powell, Felio Perez, Gerard T Rowe, Lei Yang
A series of copper complexes supported by a simple dipyridylamide ligand (H2pcp) were isolated and characterized. Treatment of H2pcp with NaH and copper(I) salts led to the formation of [Cu2(2pcp)2] (1a) and {Na[(Cu2(2pcp)2)2]PF6}n (1b). The X-ray crystal structures of both complexes feature Cu(I)Cu(I) cores with close Cu···Cu interactions. Electrochemical studies of 1a showed a reversible one-electron oxidation wave in CH2Cl2. On the basis of the work on 1a, we began studying the mixed-valence copper species supported by this ligand...
October 26, 2016: Inorganic Chemistry
Prerak Gupta, Mimi Adhikary, Joseph Christakiran M, Manishekhar Kumar, Nandana Bhardwaj, Biman B Mandal
Composite biomaterials as artificial bone graft materials are pushing the present frontiers of bioengineering. In this study, a biomimetic, osteoconductive tricomposite scaffold made of hydroxyapatite (HA) embedded in non-mulberry Antheraea assama (A. assama) silk fibroin fibers and its fibroin solution is explored for osteogenic potential. Scaffolds were physico-chemically characterized for morphology, porosity, secondary structure conformation, water retention ability, biodegradability and mechanical property...
October 26, 2016: ACS Applied Materials & Interfaces
Morten Beck Trelle, Shona H Pedersen, Eva Christina Østerlund, Jeppe Buur Madsen, Søren Risom Kristensen, Thomas J D Jørgensen
Antithrombin deficiency is associated with increased risk of venous thrombosis. In certain families this condition is caused by pathogenic polymerization of mutated antithrombin in the blood. To facilitate future development of pharmaceuticals against antithrombin polymerization an improved understanding of the polymerogenic intermediates is crucial. However, X-ray crystallography of these intermediates is severely hampered by the difficulty in obtaining well-diffracting crystals of transient and heterogeneous noncovalent protein assemblies...
October 26, 2016: Analytical Chemistry
Sergey N Konchenko, Svetlana V Klementieva, Nina P Gritsan, Marat M Khusniyarov, Alexander Witt, Alexey A Dmitriev, Elizaveta A Suturina, Nathan D D Hill, Tracey L Roemmele, Michael T, René T Boeré, Peter W Roesky, Andrey V Zibarev
The first lanthanide complexes with a redox-active sulphur diimide ligand, [LnCp*2(Me3SiN=)2S] (Ln = Sm, Eu, Yb; Cp* = η5-C5Me5), are reported. The complexes were synthesized using [LnCp*2(THF)2] and (Me3SiN=)2S and have been thoroughly characterized by single-crystal X-ray diffraction, EPR spectroscopy, UV-Vis-NIR electronic absorption spectroscopy and SQUID magnetometry. The results, as interpreted by CASSCF/SOC-RASSI calculations providing a non-perturbative treatment of spin-orbit coupling, indicate that these paramagnetic complexes are best described as Ln3+ and [(Me3SiN=)2S]-* adducts...
October 26, 2016: Chemistry: a European Journal
GuiYun Hang, WenLi Yu, Tao Wang, Zhen Li
In order to determine the adsorption mechanism of water on the crystal surfaces of the explosive JOB-9003 and the effect of this adsorption on the sensitivity and detonation performance of this explosive, a model of the crystal of JOB-9003 was created in the software package Materials Studio (MS). The adsorption process was simulated, and molecular dynamics simulation was performed with the COMPASS force field in the NPT ensemble to calculate the sensitivity and detonation performance of the explosive. The results show that the maximum trigger bond length decreases whereas the interaction energy of the trigger bond and the cohesive energy density increase after adsorption, indicating that the sensitivity of JOB-9003 decreases...
November 2016: Journal of Molecular Modeling
Marcin Krawczyk, Piero Portincasa, Frank Lammert
No abstract text is available yet for this article.
October 25, 2016: Journal of Pediatric Gastroenterology and Nutrition
Kerry Marie Goodman, Rotem Rubinstein, Chan Aye Thu, Seetha Mannepalli, Fabiana Bahna, Göran Ahlsén, Chelsea Rittenhouse, Tom Maniatis, Barry Honig, Lawrence Shapiro
Stochastic cell-surface expression of α-, β-, and γ-clustered protocadherins (Pcdhs) provides vertebrate neurons with single-cell identities that underlie neuronal self-recognition. Here we report crystal structures of ectodomain fragments comprising cell-cell recognition regions of mouse γ-Pcdhs γA1, γA8, γB2, and γB7 revealing trans-homodimers, and of C-terminal ectodomain fragments from γ-Pcdhs γA4 and γB2, which depict cis-interacting regions in monomeric form. Together these structures span the entire Pcdhγ ectodomain...
October 26, 2016: ELife
Dalei Wu, Xiaoyu Su, Nalini Potluri, Youngchang Kim, Fraydoon Rastinejad
The neuronal PAS domain proteins NPAS1 and NPAS3 are members of the basic helix-loop-helix-PER-ARNT-SIM (bHLH-PAS) family, and their genetic deficiencies are linked to a variety of human psychiatric disorders including schizophrenia, autism spectrum disorders and bipolar disease. NPAS1 and NPAS3 must each heterodimerize with the aryl hydrocarbon receptor nuclear translocator (ARNT), to form functional transcription complexes capable of DNA binding and gene regulation. Here we examined the crystal structures of multi-domain NPAS1-ARNT and NPAS3-ARNT-DNA complexes, discovering each to contain four putative ligand-binding pockets...
October 26, 2016: ELife
Zhaodong Liu, Zhen Yao, Mingguang Yao, Jiayin Lv, Shuanglong Chen, Quanjun Li, Hang Lv, Tianyi Wang, Shuangchen Lu, Ran Liu, Bo Liu, Jing Liu, Zhiqiang Chen, Bo Zou, Tian Cui, Bingbing Liu
We present a joint experimental and theoretical study on the high-pressure behavior of bromine confined in the one-dimensional (1D) nanochannels of zeolite AlPO4-5 (AFI) single crystals. Raman scattering experiments indicate that loading bromine into AFI single crystals can lead to the formation of bromine molecular chains inside the nanochannels of the crystals. High-pressure Raman and X-ray diffraction studies demonstrate that high pressure can increase the length of the confined bromine molecular chains and modify the inter- and intramolecular interactions of the molecules...
September 28, 2016: Journal of Chemical Physics
S Paoloni, F Mercuri, U Zammit
In this work we use a photopyroelectric calorimetric set up to analyze the transformations occurring in thin samples of liquid crystal-microemulsion system by combining the results of the simultaneously performed high temperature resolution polarization microscopy observations and the temperature dependence of the specific heat, and of the thermal conductivity. This enabled an accurate direct correlation of the observations concerning the different measured quantities for a most comprehensive interpretation of the obtained results...
September 28, 2016: Journal of Chemical Physics
Yicun Ni, J L Skinner
No man's land is the region in the metastable phase diagram of water where it is very difficult to do experiments on liquid water because of homogeneous nucleation to the crystal. There are a number of estimates of the location in no man's land of the liquid-liquid critical point, if it exists. We suggest that published IR absorption experiments on water droplets in no man's land can provide information about the correct location. To this end, we calculate theoretical IR spectra for liquid water over a wide range of temperatures and pressures, using our E3B3 model, and use the results to argue that the temperature dependence of the experimental spectra is inconsistent with several of the estimated critical point locations, but consistent with others...
September 28, 2016: Journal of Chemical Physics
Luigi Cannavacciuolo, Jürg Hulliger
Stochastic formation of a bi-polar state in three dimensional arrays of polar molecules with full Coulomb interactions is reproduced by Monte Carlo simulation. The size of the system is comparable to that of a real crystal seed. The spatial decay of the average order parameter is significantly slowed down by the long range interactions and the exact representation of correlation effects in terms of a single characteristic length becomes impossible. Finite size effects and possible scale invariance symmetry of the order parameter are extensively discussed...
September 28, 2016: Journal of Chemical Physics
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"