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Membrane protein crystalization

Agnieszka Mierczynska-Vasilev, Paul A Smith
The adsorption of macromolecules on solid surfaces is of great importance in the field of nanotechnology, biomaterials, biotechnological, and food processes. In the field of oenology adsorption of wine macromolecules such as polyphenols, polysaccharides, and proteins is much less desirable on membrane materials because of fouling and reduced filtering performance. On the other hand, adsorption of these molecules on processing aids is very beneficial for achieving wine clarity and stability. In this article, the effect of surface chemical functionalities on the adsorption of white, rosé, and red wine constituents was evaluated...
October 18, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Crystal N Marconett, Beiyun Zhou, Mitsuhiro Sunohara, Tiffany M Pouldar, HongJun Wang, Yixin Liu, Megan E Rieger, Evelyn Tran, Per Flodby, Kimberly D Siegmund, Edward D Crandall, Ite A Laird-Offringa, Zea Borok
Diseases involving the distal lung alveolar epithelium include chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF) and lung adenocarcinoma. Accurate labeling of specific cell types is critical for determining the contribution of each to pathogenesis of these diseases. The distal lung alveolar epithelium is comprised of two cell types, alveolar epithelial type 1 (AT1) and type 2 (AT2) cells. While cell type-specific markers, most prominently surfactant protein C (SFTPC), have allowed detailed lineage tracing studies of AT2 cell differentiation and their roles in disease, studies of AT1 cells have been hampered by lack of genes with expression unique to AT1 cells...
October 17, 2016: American Journal of Respiratory Cell and Molecular Biology
Mauricio Toro-Nahuelpan, Frank D Müller, Stefan Klumpp, Jürgen M Plitzko, Marc Bramkamp, Dirk Schüler
BACKGROUND: The navigation of magnetotactic bacteria relies on specific intracellular organelles, the magnetosomes, which are membrane-enclosed crystals of magnetite aligned into a linear chain. The magnetosome chain acts as a cellular compass, aligning the cells in the geomagnetic field in order to search for suitable environmental conditions in chemically stratified water columns and sediments. During cytokinesis, magnetosome chains have to be properly positioned, cleaved and separated in order to be evenly passed into daughter cells...
October 12, 2016: BMC Biology
Peter M Waziri, Rasedee Abdullah, Swee Keong Yeap, Abdul Rahman Omar, Ahmad Bustamam Abdul, Nur Kartinee Kassim, Ibrahim Malami, Thiruventhan Karunakaran, Mustapha Umar Imam
ETHNOPHARMACOLOGICAL RELEVANCE: Clausena excavata Burm.f. is used locally in folk medicine for the treatment of cancer in South East Asia. AIM OF THE STUDY: To determine the mechanism action of pure clausenidin crystals in the induction hepatocellular carcinoma (hepG2) cells apoptosis. MATERIALS AND METHODS: Pure clausenidin was isolated from Clausena excavata Burm.f. and characterized using (1)H and (13)C NMR spectra. Clausenidin-induced cytotoxicity was determined by MTT assay...
October 8, 2016: Journal of Ethnopharmacology
Tamas Yelland, Snezana Djordjevic
Neuropilins (NRPs) are single-pass transmembrane receptors involved in several signaling pathways that regulate key physiological processes such as vascular morphogenesis and axon guidance. The MAM domain of NRP, which has previously been implicated in receptor multimerization, was the only portion of the ectopic domain of the NRPs for which the structure, until now, has been elusive. Using site-directed mutagenesis in the linker region preceding the MAM domain we generated a protein construct amenable to crystallization...
October 3, 2016: Structure
C Satriano, G Lupo, C Motta, C D Anfuso, P Di Pietro, B Kasemo
Hybrid nanoassemblies of ferritin and silica-supported lipid bilayers (ferritin-SLBs) have been prepared and tested for the adhesion, spreading and proliferation of retinal microvascular endothelial cells (ECs). Lipid membranes with varying surface charge were obtained by mixing cationic 1-palmitoyl-2-oleoyl-sn-glycero-3-ethylphosphocholine (POEPC) with zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) at increasing POPC/POEPC ratios. The supported bilayer formation and their subsequent interaction processes with ferritin were studied at the pH of 7...
October 4, 2016: Colloids and Surfaces. B, Biointerfaces
Deepika Aggarwal, Diksha Gautam, Minu Sharma, S K Singla
Bergenin, isolated from Bergenia ligulata is a potent antioxidant and antilithiatic agent. Present work was designed to establish the biochemical role of bergenin on mitochondrial dysfunction in the ethylene glycol induced hyperoxaluric rat model. Bergenin was administrated at a dose of 10mg/kg body wt i.p. from 14th day of establishing the 28 days hyperoxaluria rat model. α-Tocopherol was given as positive control at a dose of 100mg/kg body wt i.p. Mitochondrial dysfunction was studied by evaluating the activities of respiratory chain complexes, mitochondrial membrane potential and reactive oxygen species...
October 5, 2016: European Journal of Pharmacology
Trent Conroy, Madhura Manohar, Yu Gong, Shane M Wilkinson, Michael Webster, Brian P Lieberman, Samuel D Banister, Tristan A Reekie, Robert H Mach, Louis M Rendina, Michael Kassiou
The sigma-1 receptor (S1R) has attracted a great deal of attention as a prospective drug target due to its involvement in numerous neurological disorders and, more recently, for its therapeutic potential in neuropathic pain. As there was no crystal structure of this membrane-bound protein reported until 2016, ligand generation was driven by pharmacophore refinements to the general model suggested by Glennon and co-workers. The generalised S1R pharmacophore comprises a central region where a basic amino group is preferred, flanked by two hydrophobic groups...
October 4, 2016: Organic & Biomolecular Chemistry
Zhijie Li, Sayan Chakraborty, Guozhou Xu
Does not respond to nucleotides 1 (DORN1) has recently been identified as the first membrane-integral plant ATP receptor, which is required for ATP-induced calcium response, mitogen-activated protein kinase activation and defense responses in Arabidopsis thaliana. In order to understand DORN1-mediated ATP sensing and signal transduction, crystallization and preliminary X-ray studies were conducted on the extracellular domain of DORN1 (atDORN1-ECD) and that of an orthologous protein, Camelina sativa lectin receptor kinase I...
October 1, 2016: Acta Crystallographica. Section F, Structural Biology Communications
Dongdi Li, Ruth Moorman, Thomas Vanhercke, James Petrie, Surinder Singh, Colin J Jackson
Membrane fatty acid desaturases are a diverse superfamily of enzymes that catalyze the introduction of double bonds into fatty acids. They are essential in a range of metabolic processes, such as the production of omega-3 fatty acids. However, our structure-function understanding of this superfamily is still developing and their range of activities and substrate specificities are broad, and often overlapping, which has made their systematic characterization challenging. A central issue with characterizing these proteins has been the lack of a structural model, which has been overcome with the recent publication of the crystal structures of two mammalian fatty acid desaturases...
2016: Computational and Structural Biotechnology Journal
Luana G M Ferrara, Gregor D Wallat, Lucile Moynié, Naresh N Dhanasekar, Soumeya Aliouane, Silvia Acosta-Gutiérrez, Jean-Marie Pagès, Jean-Michel Bolla, Mathias Winterhalter, Matteo Ceccarelli, James H Naismith
The Gram-negative organism Campylobacter jejuni is the major cause of food poisoning. Unlike Escherichia coli, which has two major porins, OmpC and OmpF, C. jejuni has one, termed major outer membrane protein (MOMP) through which nutrients and antibiotics transit. We report the 2.1-Å crystal structure of C. jejuni MOMP expressed in E. coli and a lower resolution but otherwise identical structure purified directly from C. jejuni. The 2.1-Å resolution structure of recombinant MOMP showed that although the protein has timeric arrangement similar to OmpC, it is an 18-stranded, not 16-stranded, β-barrel...
September 30, 2016: Journal of Molecular Biology
Alexei Gorelik, Leonhard X Heinz, Katalin Illes, Giulio Superti-Furga, Bhushan Nagar
The enzyme acid sphingomyelinase-like phosphodiesterase 3B (SMPDL3B) was shown to act as a negative regulator of innate immune signaling, affecting cellular lipid composition and membrane fluidity. Furthermore, several reports identified this enzyme as an off-target of the therapeutic antibody rituximab, with implications in kidney disorders. However, structural information for this protein is lacking. Here we present the high-resolution crystal structure of murine SMPDL3B which reveals a substrate binding site strikingly different from its paralogs...
September 28, 2016: Journal of Biological Chemistry
Le Thi My Le, Wonchull Kang, Ji-Yun Kim, Oanh Thi Tu Le, Sang Yoon Lee, Jin Kuk Yang
The hexameric ATPase p97 has been implicated in diverse cellular processes through interactions with many different adaptor proteins at its N-terminal domain. Among these, the Ufd1-Npl4 heterodimer is a major adaptor, and the p97-Ufd1-Npl4 complex plays an essential role in endoplasmic reticulum-associated degradation (ERAD), acting as a segregase that translocates the ubiquitinated client protein from the ER membrane into the cytosol for proteasomal degradation. We determined the crystal structure of the complex of the N-terminal domain of p97 and the SHP box of Ufd1 at a resolution of 1...
2016: PloS One
Andrii Ishchenko, Vadim Cherezov, Wei Liu
Membrane proteins (MPs) are essential components of cellular membranes and primary drug targets. Rational drug design relies on precise structural information, typically obtained by crystallography; however MPs are difficult to crystallize. Recent progress in MP structural determination has benefited greatly from the development of lipidic cubic phase (LCP) crystallization methods, which typically yield well-diffracting, but often small crystals that suffer from radiation damage during traditional crystallographic data collection at synchrotron sources...
2016: Journal of Visualized Experiments: JoVE
Pradeep Sathyanarayana, Rajat Desikan, K Ganapathy Ayappa, Sandhya S Visweswariah
Pore-forming toxins (PFTs) bind to cell membranes and form nanoscale pores that allow leakage of cellular components, resulting in cell death. The water-soluble, monomeric form of these toxins shows a dramatic conformational change during pore formation, as exemplified by crystal structures of the monomer and functional pore of cytolysin A (ClyA). The solvent-exposed, C-terminal residues of the protein are essential for activity, but the mechanism by which this region regulates pore formation remains unknown...
October 13, 2016: Biochemistry
Xiaoran Wei, Xiaolei Qu, Lei Ding, Jingtian Hu, Wei Jiang
Silica nanoparticles (SiO2 NPs) can cause health hazard after their release into the environment. Adsorption of natural organic matter and biomolecules on SiO2 NPs alters their surface properties and cytotoxicity. In this study, SiO2 NPs were treated by bovine serum albumin (BSA) and humic acid (HA) to study their effects on the integrity and fluidity of model cell membranes. Giant and small unilamellar vesicles (GUVs and SUVs) were prepared as model cell membranes in order to avoid the interference of cellular activities...
September 20, 2016: Environmental Pollution
James Barber
About 3 billion years ago an enzyme emerged which would dramatically change the chemical composition of our planet and set in motion an unprecedented explosion in biological activity. This enzyme used solar energy to power the thermodynamically and chemically demanding reaction of water splitting. In so doing it provided biology with an unlimited supply of reducing equivalents needed to convert carbon dioxide into the organic molecules of life while at the same time produced oxygen to transform our planetary atmosphere from an anaerobic to an aerobic state...
January 2016: Quarterly Reviews of Biophysics
Linlin Zhao, Shuqing Wang, Changqing Run, Bo OuYang, James J Chou
Many membrane proteins bind specifically to lipids as an integral component of their structures. The ability of detergents to support lipid binding is thus an important consideration when solubilizing membrane proteins for structural studies. In particular, the zwitterionic phosphocholine (PC)-based detergents, which have been widely used in solution NMR studies of channels and transporters, are controversial because of their strong solubilization power and thus perceived as more denaturing than nonionic detergents such as the maltosides...
September 27, 2016: Biochemistry
Reinhard I Boysen, Lachlan J Schwarz, Dan V Nicolau, Milton T W Hearn
This review describes recent advances associated with the development of surface imprinting methods for the synthesis of polymeric membranes and thin films, which possess the capability to selectively and specifically recognize biomacromolecules, such as proteins and single- and double-stranded DNA, employing "epitope" or "whole molecule" approaches. Synthetic procedures to create different molecularly imprinted polymer membranes or thin films are discussed, including grafting/in situ polymerization, drop-, dip-, or spin-coating procedures, electropolymerization as well as micro-contact or stamp lithography imprinting methods...
September 12, 2016: Journal of Separation Science
Saziye Yorulmaz, Joshua A Jackman, Walter Hunziker, Nam-Joon Cho
The complement system is an important part of the innate immune response, and there is great interest in understanding how complement proteins interact with lipid membrane interfaces, especially in the context of recognizing foreign particulates (e.g., liposomal nanomedicines). Herein, a supported lipid bilayer platform was employed in order to investigate the effect of membrane surface charge (positive, negative, or neutral) on the adsorption of three complement proteins. Quartz crystal microbalance-dissipation (QCM-D) experiments measured the real-time kinetics and total uptake of protein adsorption onto supported lipid bilayers...
August 22, 2016: Colloids and Surfaces. B, Biointerfaces
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