557 research outputs found

    Правове регулювання безоплатної приватизації земель запасу

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    Досліджуються правові підстави безоплатної приватизації земель запасу. Автор виокремлює два її різновиди – гарантовану і негарантовану. Розкриваються особли­вості багатоетапної процедури реалізації права на безоплатну приватизацію земель запасу в Україні.Исследуются правовые основания бесплатной приватизации земель запаса. Автор разделяет два ее разновидности – гарантированную и негарантированную. Раскрыва­ются особенности многоэтапной процедуры реализации права на бесплатную прива­тизацию земель в Украине.Legal rules about free of payment land privatization are investigated. The author pro­poses dividing free of payment land privatization into two varieties: guaranteed and non­guaranteed ones. Legal peculiarities of multistoried procedure of free of payment land priva­tization in Ukraine are disclosed

    Diketo acids inhibit the cap-snatching endonuclease of several Bunyavirales

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    Several fatal bunyavirus infections lack specific treatment. Here, we show that diketo acids engage a panel of bunyavirus cap-snatching endonucleases, inhibit their catalytic activity and reduce viral replication of a taxonomic representative in vitro. Specifically, the non-salt form of L-742,001 and its derivatives exhibited EC50 values between 5.6 to 6.9 μM against a recombinant BUNV-mCherry virus. Structural analysis and molecular docking simulations identified traits of both the class of chemical entities and the viral target that could help the design of novel, more potent molecules for the development of pan-bunyavirus antivirals

    Structural modification of fibroblast growth factor-binding heparan sulfate at a determinative stage of neural development

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    Heparan sulfate (HS) glycosaminoglycans are essential modulators of fibroblast growth factor (FGF) activity and appear to act by coupling particular forms of FGF to appropriate FGF receptors, During neural development, one particular HS proteoglycan is able to rapidly switch its potentiating activity from FGF-2, as neural precursor cell proliferation occurs, to FGF-1, as neuronal differentiation occurs, Using various analytical techniques, including chemical and enzymatic cleavage, low pressure chromatography, and strong anion-exchange high performance Liquid chromatography, we have analyzed the different HSs expressed during these crucial developmental stages, There are distinct alterations in patterns of 6-O-sulfation, total chain length, and the number of sulfated domains of the HS from the more mature embryonic brain, These changes correlate with a switch in the ability of the HS to potentiate the actions of FGF-1 in triggering: cell differentiation It thus appears that each HS pool is designed to function in the modulation of an intricate interaction with a specific growth factor and its cognate receptor, and suggests tightly regulated expression of specific, bioactive disaccharide sequences, The data can be used to construct a simple model of controlled variations in HS chain structure which have functional consequences at a crucial stage of neuronal maturation

    Inferring stabilizing mutations from protein phylogenies : application to influenza hemagglutinin

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    One selection pressure shaping sequence evolution is the requirement that a protein fold with sufficient stability to perform its biological functions. We present a conceptual framework that explains how this requirement causes the probability that a particular amino acid mutation is fixed during evolution to depend on its effect on protein stability. We mathematically formalize this framework to develop a Bayesian approach for inferring the stability effects of individual mutations from homologous protein sequences of known phylogeny. This approach is able to predict published experimentally measured mutational stability effects (ΔΔG values) with an accuracy that exceeds both a state-of-the-art physicochemical modeling program and the sequence-based consensus approach. As a further test, we use our phylogenetic inference approach to predict stabilizing mutations to influenza hemagglutinin. We introduce these mutations into a temperature-sensitive influenza virus with a defect in its hemagglutinin gene and experimentally demonstrate that some of the mutations allow the virus to grow at higher temperatures. Our work therefore describes a powerful new approach for predicting stabilizing mutations that can be successfully applied even to large, complex proteins such as hemagglutinin. This approach also makes a mathematical link between phylogenetics and experimentally measurable protein properties, potentially paving the way for more accurate analyses of molecular evolution

    Measurement of Nanomolar Dissociation Constants by Titration Calorimetry and Thermal Shift Assay – Radicicol Binding to Hsp90 and Ethoxzolamide Binding to CAII

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    The analysis of tight protein-ligand binding reactions by isothermal titration calorimetry (ITC) and thermal shift assay (TSA) is presented. The binding of radicicol to the N-terminal domain of human heat shock protein 90 (Hsp90αN) and the binding of ethoxzolamide to human carbonic anhydrase (hCAII) were too strong to be measured accurately by direct ITC titration and therefore were measured by displacement ITC and by observing the temperature-denaturation transitions of ligand-free and ligand-bound protein. Stabilization of both proteins by their ligands was profound, increasing the melting temperature by more than 10 ºC, depending on ligand concentration. Analysis of the melting temperature dependence on the protein and ligand concentrations yielded dissociation constants equal to 1 nM and 2 nM for Hsp90αN-radicicol and hCAII-ethoxzolamide, respectively. The ligand-free and ligand-bound protein fractions melt separately, and two melting transitions are observed. This phenomenon is especially pronounced when the ligand concentration is equal to about half the protein concentration. The analysis compares ITC and TSA data, accounts for two transitions and yields the ligand binding constant and the parameters of protein stability, including the Gibbs free energy and the enthalpy of unfolding

    Production and characterisation of a recombinant scFv reactive with human gastrointestinal carcinomas

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    SC142-reactive antigen are highly glycosylated glycoproteins expressed on tissues of gastric and colon cancers but not on normal tissues. Murine SC142 antibody specific for the SC142-reactive antigen has been produced by immunisation with SNU16 stomach cancer cells. However, SC142 antibody has several potential problems such as high immunogenicity and poor tumour penetration owing to their large size. To improve tumour penetration potential in vivo, recombinant single-chain fragments have been produced using the original hybridoma cells as a source of variable heavy- and variable light-chain-encoding antibody genes. The use of the polymerase chain reaction, expression cloning technology and gene expression systems in E. coli has led to the production of SC142 single-chain fragments, which was similar in activity to the SC142 parent antibody confirmed by immunohistochemistry. Analysis by DNA sequencing, SDS–PAGE and Western blotting has demonstrated the integrity of the single-chain fragments. Competitive ELISA showed that SC142 single-chain fragments originated from parent SC142 antibody. BIAcore biosensor binding experiments showed that the SC142 single-chain fragments had an ideal dissociation rate constant as a tumour imaging reagent. These results illustrate the potential application of these novel products as an immunodiagnostic and further immunotherapeutic reagent

    Binding Properties and Stability of the Ras-Association Domain of Rap1-GTP Interacting Adapter Molecule (RIAM)

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    The Rap1-GTP interacting adapter protein (RIAM) is an important protein in Rap1-mediated integrin activation. By binding to both Rap1 GTPase and talin, RIAM recruits talin to the cell membrane, thus facilitating talin-dependent integrin activation. In this article, we studied the role of the RIAM Ras-association (RA) and pleckstrin-homology (PH) domains in the interaction with Rap1. We found that the RA domain was sufficient for GTP-dependent interaction with Rap1B, and the addition of the PH domain did not change the binding affinity. We also detected GTP-independent interaction of Rap1B with the N-terminus of RIAM. In addition, we found that the PH domain stabilized the RA domain both in vitro and in cells

    Crystal cookery – using high-throughput technologies and the grocery store as a teaching tool

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    Using high-throughput crystallization screening technologies and data analysis, an educational program has been developed to teach the scientific method through crystallization and access to a grocery store, a post office and the internet

    X-Ray Structure of the Human Calreticulin Globular Domain Reveals a Peptide-Binding Area and Suggests a Multi-Molecular Mechanism

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    In the endoplasmic reticulum, calreticulin acts as a chaperone and a Ca2+-signalling protein. At the cell surface, it mediates numerous important biological effects. The crystal structure of the human calreticulin globular domain was solved at 1.55 Å resolution. Interactions of the flexible N-terminal extension with the edge of the lectin site are consistently observed, revealing a hitherto unidentified peptide-binding site. A calreticulin molecular zipper, observed in all crystal lattices, could further extend this site by creating a binding cavity lined by hydrophobic residues. These data thus provide a first structural insight into the lectin-independent binding properties of calreticulin and suggest new working hypotheses, including that of a multi-molecular mechanism
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