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Dana R Sax, Dustin G Mark, Renee Y Hsia, Thida C Tan, Grace H Tabada, Alan S Go
BACKGROUND: Although 80% of patients with heart failure seen in the emergency department (ED) are admitted, less is known about short-term outcomes and demand for services among discharged patients. METHODS AND RESULTS: We examined adult members of a large integrated delivery system who visited an ED for acute heart failure and were discharged from January 1, 2013, through September 30, 2014. The primary outcome was a composite of repeat ED visit, hospital admission, or death within 7 days of discharge...
December 2017: Circulation. Heart Failure
Giorgio E Tamò, Luciano A Abriata, Giulia Fonti, Matteo Dal Peraro
Integrative modeling approaches attempt to combine experiments and computation to derive structure-function relationships in complex molecular assemblies. Despite their importance for the advancement of life sciences, benchmarking of existing methodologies is rather poor. The 12th round of the Critical Assessment of protein Structure Prediction (CASP) offered a unique niche to benchmark data and methods from two kinds of experiments often used in integrative modeling, namely residue-residue contacts obtained through crosslinking/mass-spectrometry (CLMS), and small-angle X-ray scattering (SAXS) experiments...
December 13, 2017: Proteins
Antje Ziller, Sara S Nogueira, Eva Huehn, Sergio S Funari, Gerald Brezesinski, Hermann Hartmann, Ugur Sahin, Heinrich Haas, Peter Langguth
Insertion of high molecular weight messenger RNA (mRNA) into lyotropic lipid phases as model systems for controlled release formulations for the mRNA was investigated. Low fractions of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) were used as an anchor to load the mRNA into a lamellar lipid matrix. Dispersions of zwitterionic lipid in the aqueous phase in the presence of increasing fractions of mRNA and cationic lipid were prepared, and the molecular organization was investigated as a function of mRNA and cationic lipid fraction...
December 12, 2017: Molecular Pharmaceutics
Zhenzheng Hu, Xiangyi Shi, Bowen Yu, Na Li, Ying Huang, Yongning He
Mannose receptor (MR, CD206) is an endocytic receptor on microphages and dendritic cells. It recognizes multiple ligands and plays important roles in regulating immune responses and maintaining glycoprotein homeostasis. However, the structure and functional mechanism of MR remain unclear. Here we determine the crystal structures of the N-terminal fragments of MR and reveal the potential binding mode of collagen on the fibronectin II domain. The SAXS and other biophysical data suggest that MR adopts an extended conformation at physiological pH and undergoes conformational changes as pH decreases, resulting in a compact conformation in an acidic environment...
December 6, 2017: Structure
V M Gun'ko, T V Krupska, L S Andriyko, N Yu Klymenko, I V Siora, O A Novikova, A I Marynin, A I Ukrainets, B Charmas, S B Shekhunova, V V Turov
Interaction of doxorubicin hydrochloride (DOX) (anti-cancer drug) with hydro-compacted nanosilica A-300 (cA-300) alone or cA-300/human serum albumin (HSA) at a small content of water (h = 0.4 g per gram of dry silica) in different dispersion media (air, chloroform, and chloroform/trifluoroacetic acid) was analyzed using low-temperature 1H NMR spectroscopy, NMR cryoporometry and quantum chemistry to elucidate specific changes in the interfacial layers. Initial (bulk density ρb ≈ 0.046 g/cm3) and hydro-compacted (ρb ≈ 0...
December 5, 2017: Journal of Colloid and Interface Science
Marco Antonio Seiki Kadowaki, Paula Higasi, Mariana Ortiz de Godoy, Rolf A Prade, Igor Polikarpov
Cellobiohydrolases hydrolyze cellulose, a linear polymer with glucose monomers linked exclusively by β-1,4 glycosidic linkages. The widespread hydrogen bonding network tethers individual cellulose polymers forming crystalline cellulose, which prevent the access of hydrolytic enzymes and water molecules. The most abundant enzyme secreted by Myceliophthora thermophila M77 in response to the presence of biomass is the cellobiohydrolase MtCel7A, which is composed by a GH7-catalytic domain (CD), a linker and a CBM1-type carbohydrate binding module...
December 8, 2017: FEBS Journal
An Hsieh, Lanyuan Lu, Mark R Chance, Sichun Yang
Integrative structure modeling is an emerging method for structural determination of protein-protein complexes that are challenging for conventional structural techniques. Here, we provide a practical protocol for implementing our integrated iSPOT platform by integrating three different biophysical techniques: small-angle X-ray scattering (SAXS), hydroxyl radical footprinting, and computational docking simulations. Specifically, individual techniques are described from experimental and/or computational perspectives, and complementary structural information from these different techniques are integrated for accurate characterization of the structures of large protein-protein complexes...
2017: Advances in Experimental Medicine and Biology
Alexander V Grishaev
Biomolecular applications of solution X-ray and neutron scattering (SAXS and SANS, respectively) started in late 1960s - early 1970s but were relatively limited in their ability to provide a detailed structural picture and lagged behind what became the two primary methods of experimental structural biology - X-ray crystallography and NMR. However, improvements in both data analysis and instrumentation led to an explosive growth in the number of studies that used small-angle scattering (SAS) for investigation of macromolecular structure, often in combination with other biophysical techniques...
2017: Advances in Experimental Medicine and Biology
Frank Gabel
Small angle neutron scattering (SANS) is a powerful tool to obtain structural information on solubilized membrane proteins on the nanometer length-scale in complement to other structural biology techniques such as cryo-EM, NMR and SAXS. In combination with deuteration of components and/or contrast variation (H2O:D2O exchange in the buffer) SANS allows to separate structural information from the protein and the detergent/lipid parts in solution. After a short historical overview on results obtained by SANS on membrane protein systems, this book chapter introduces the basic theoretical principles of the technique as well as requirements on samples...
2017: Advances in Experimental Medicine and Biology
Javier Pérez, Patrice Vachette
A monodispersed and ideal solution is a central (unique?) requirement of SAXS to allow one to extract structural information from the recorded pattern. On-line Size Exclusion Chromatography (SEC) marked a major breakthrough, separating particles present in solution according to their size. Identical frames under an elution peak can be averaged and further processed free from contamination. However, this is not always straightforward, separation is often incomplete and software have been developed to deconvolve the contributions from the different species (molecules or oligomeric forms) within the sample...
2017: Advances in Experimental Medicine and Biology
Yujing Wang, Hao Zhou, Emre Onuk, John Badger, Lee Makowski
Extending collection of x-ray solution scattering data into the wide-angle regime (WAXS) can provide information not readily extracted from small angle (SAXS) data. It is possible to accurately predict WAXS scattering on the basis of atomic coordinate sets and thus use it as a means of testing molecular models constructed on the basis of crystallography, molecular dynamics (MD), cryo-electron microscopy or ab initio modeling. WAXS data may provide insights into the secondary, tertiary and quaternary structural organization of macromolecules...
2017: Advances in Experimental Medicine and Biology
Tiago N Cordeiro, Fátima Herranz-Trillo, Annika Urbanek, Alejandro Estaña, Juan Cortés, Nathalie Sibille, Pau Bernadó
Intrinsically Disordered Proteins (IDPs) are fundamental actors of biological processes. Their inherent plasticity facilitates very specialized tasks in cell regulation and signalling, and their malfunction is linked to severe pathologies. Understanding the functional role of disorder requires the structural characterization of IDPs and the complexes they form. Small-angle Scattering of X-rays (SAXS) and Neutrons (SANS) have notably contributed to this structural understanding. In this review we summarize the most relevant developments in the field of SAS studies of disordered proteins...
2017: Advances in Experimental Medicine and Biology
Maxim V Petoukhov, Anne Tuukkanen
Small angle scattering of X-rays (SAXS) and neutrons (SANS) is a structural technique to study disordered systems with chaotic orientations of scattering inhomogeneities at low resolution. An important example of such systems are solutions of biological macromolecules. Rapid development in the methodology for solution scattering data interpretation and model building during the last two decades brought the analysis far beyond the determination of just few overall structural parameters (which was the only possibility in the past) and ensured SAS a firm position in the methods palette of the modern life sciences...
2017: Advances in Experimental Medicine and Biology
Robert P Rambo
The success of a SAXS experiment for structural investigations depends on two precise measurements, the sample and the buffer background. Buffer matching between the sample and background can be achieved using dialysis methods but in biological SAXS of monodisperse systems, sample preparation is routinely being performed with size exclusion chromatography (SEC). SEC is the most reliable method for SAXS sample preparation as the method not only purifies the sample for SAXS but also almost guarantees ideal buffer matching...
2017: Advances in Experimental Medicine and Biology
Melissa A Graewert, Cy M Jeffries
In this book chapter, a practical approach for conducting small angle X-ray scattering (SAXS) experiments is given. Our aim is to guide SAXS users through a three-step process of planning, preparing and performing a basic SAXS measurement. The minimal requirements necessary to prepare samples are described specifically for protein and other macromolecular samples in solution. We address the very important aspects in terms of sample characterization using additional techniques as well as the essential role of accurately subtracting background scattering contributions...
2017: Advances in Experimental Medicine and Biology
Giuseppe Graziano
In a recent article, A. Battisti et al., Phys. Chem. Chem. Phys., 2017, 19, 8435, results from SAXS measurements, metadynamic trajectories and classic MD trajectories at different temperatures have been used to study the temperature-induced compaction of the intrinsically disordered protein tau. The analysis, though technically sound, does not provide a clear explanation of hydrophobic interaction strengthening on increasing the temperature and its relationship with the population increase of secondary structural elements...
December 8, 2017: Physical Chemistry Chemical Physics: PCCP
Junju Mu, Ryuhei Motokawa, Kazuhiro Akutsu, Shotaro Nishitsuji, Andrew J Masters
We present evidence that the organic/third phase transition, as may be observed in the Plutonium Uranium Reduction EXtraction process (PUREX) at high metal loading, is an unusual transition between two isotropic, bi-continuous micro-emulsion phases. As this system contains so many components, however, we seek first to investigate the properties of a simpler system, viz. the related metal-free, quaternary system of water/n-dodecane/nitric acid/tri-butyl phosphate (TBP). Under appropriate conditions, this system exhibits three coexisting phases, namely the light organic phase, the third phase and the aqueous phase...
December 7, 2017: Journal of Physical Chemistry. B
Patrick E J Saloga, Claudia Kästner, Andreas F Thünemann
Ever since reaction procedures are improved to achieve higher yields and shorter reaction times. One possibility consists in the usage of microwave reactors. In literature this is under discussion since they claim non-thermal effects resulting from the microwave radiation. Especially for the synthesis of nano-materials it is of crucial importance to be aware of influences on the reaction pathway. Therefore, we compare the syntheses of ultra-small silver nanoparticles via conventional and microwave heating. We employed a versatile one-pot polyol synthesis of poly(acrylic acid) (PAA) stabilized silver nanoparticles, which display superior catalytic properties...
December 7, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Alice Labaronne, Sigrid Milles, Amélie Donchet, Malene Ringkjøbing Jensen, Martin Blackledge, Jean-Marie Bourhis, Rob W H Ruigrok, Thibaut Crépin
Influenza viruses are negative strand RNA viruses that replicate in the nucleus of the cell. The viral nucleoprotein (NP) is the major component of the viral ribonucleoprotein. In this paper we show that the NP of influenza B has a long N-terminal tail of 70 residues with intrinsic flexibility. This tail contains the Nuclear Location Signal (NLS). The nuclear trafficking of the viral components mobilizes cellular import factors at different stages, making these host-pathogen interactions promising targets for new therapeutics...
December 7, 2017: Scientific Reports
Hongbo Yuan, Jialiang Xu, Eliane P van Dam, Giulia Giubertoni, Yves L A Rezus, Roel Hammink, Huib J Bakker, Yong Zhan, Alan E Rowan, Chengfen Xing, Paul H J Kouwer
Enhancing the thermal stability of proteins is an important task for protein engineering. There are several ways to increase the thermal stability of proteins in biology, such as greater hydrophobic interactions, increased helical content, decreased occurrence of thermolabile residues, or stable hydrogen bonds. Here, we describe a well-defined polymer based on β-helical polyisocyanotripeptides (TriPIC) that uses biological approaches, including hydrogen bonding and hydrophobic interactions for its exceptional thermal stability in aqueous solutions...
November 28, 2017: Macromolecules
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