Composition Of Such Complexes Research Articles

Rental housing. Analysis of the modern normative base

The article examines the problem of providing housing in Ukraine at the present time. The formation of a civilized rental housing market is considered an effective way to solve the problem of providing citizens with a sufficient amount of housing. An analysis of the modern regulatory framework for determining the functional affiliation of temporary accommodation facilities was carried out. Features and differences in the design of public buildings (hotels with apartments) and residential buildings are defined. Considered issues of regulatory restrictions for creating rental housing: determining the time of insolation for these apartments; determination of the maximum level of building density of rental buildings; determining the possibility of integrating public infrastructure for service into such buildings. There was a need to create a new, socially effective mechanism that would allow middle-income citizens to rent housing and improve their quality of life. Currently, the Law of Ukraine "On Rental Housing" has been developed and adopted in the first reading. According to the draft of this Law, rental housing can be located both in separate buildings and as part of multifunctional complexes. At the same time, such typological units may be included in the composition of such complexes (except for rental housing (residential apartments)), such as hotels, office premises, restaurants, cafes, commercial premises and other public premises. According to world practice, various functions in such complexes are usually distributed by height, with placement on different groups of floors. So, for example, there is a hotel on the lower floors, and residential apartments on the upper floors. At the same time, in this case, such residential apartments belong to the profitable (commercial) class. However, at present, the regulatory framework of Ukraine does not define such a typological variety as "Rental housing". Although the functional affiliation of various types of establishments for temporary accommodation of the population, such as "hotel apartments", "apart-hotels" and others, is currently defined in sufficient detail. So, in addition to legislative standardization, there is currently a task to include such type of buildings as rental residential buildings in the regulatory framework of Ukraine.

Global Identification of Protein Complexes within the Membrane Proteome of Arabidopsis Roots Using a SEC-MS Approach.

Biological processes consist of several consecutive and interacting steps as, for example, in signal transduction cascades or metabolic reaction chains. These processes are regulated by protein-protein interactions and the formation of larger protein complexes, which also occur within biological membranes. To gain a large-scale overview of complex-forming proteins and the composition of such complexes within the cellular membranes of Arabidopsis roots, we use the combination of size-exclusion chromatography and mass spectrometry. First, we identified complex-forming proteins by a retention shift analysis relative to expected retention times of monomeric proteins during size-exclusion chromatography. In a second step we predicted complex composition through pairwise correlation of elution profiles. As result we present an interactome of 963 proteins within cellular membranes of Arabidopsis roots. Identification of complex-forming proteins was highly robust between two independently grown root proteomes. The protein complex composition derived from pairwise correlations of coeluting proteins reproducibly identified stable protein complexes (ribosomes, proteasome, mitochondrial respiratory chain supercomplexes) but showed higher variance between replicates regarding transient interactions (e.g., interactions with kinases) within membrane protein complexes.

Probing Cholesterol-Dependence of Integrin-Urokinase Receptor Complex Formation using Confocal Dual-Color Fluorescence Intensity Analysis

The modern view of a plasma membrane is that of a complex supramolecular assembly of notable lipid/protein heterogeneity, in which the local lipid environment may have a profound impact on membrane protein distribution and function. Yet, the underlying mechanisms of lipid-mediated regulation of membrane protein functionality remain elusive, in part due to the limitations of existing methodologies and the often small size and transient nature of lipid/protein heterogeneities in cellular membranes. Exemplary, we still have rather limited knowledge about the significance of lipid composition in hetero-protein complex formation in such membrane systems. To address this fascinating, but poorly understood topic, here we introduce a single molecule-sensitive confocal experimental strategy, comprised of dual-color fluorescence peak analysis and photon counting histogram (PCH) method, which not only allows the detection of hetero-protein complexes in well-defined lipid environments, but also provides accurate insight into the composition of such complexes in the membrane. By applying the described methodology, here we demonstrate the formation of complexes of αvβ3 integrins and GPI-anchored urokinase plasminogen activator receptors (uPAR) in cholesterol-containing model lipid mixtures. PCH analysis of fluorescence intensity signals of complexes confirms furthermore that αvβ3-uPAR complexes are comprised of one integrin and two uPAR proteins. Remarkably, formation of comparable hetero-protein complexes is largely suppressed in a cholesterol-free lipid composition, highlighting the importance of cholesterol in αvβ3-uPAR complex formation. Our results are intriguing in light of the already established significance of cholesterol in integrin function in cellular membranes.

Ripoptosome Analysis by Caspase-8 Coimmunoprecipitation

The biochemical signaling of cell death pathways is executed at a number of different intracellular and/or membrane-bound high-molecular mass complexes. It is crucial to be able to detect the formation, differences in assembly, and differential composition of such complexes to understand their contribution to the execution phase of apoptotic or necroptotic cell death. We describe here the use of caspase-8 coimmunoprecipitation in the spontaneously transformed keratinocyte cell line, HaCaT, to study the formation and composition of the Ripoptosome, a complex that is based on the serine-threonine kinase receptor-interacting protein 1 (RIPK1). However, the method can be adapted for use with other antibodies and cell lines. This protocol determines whether cells form the Ripoptosome complex, which is important for both apoptosis and necroptosis execution. Caspase-8 is an indispensible Ripoptosome component; therefore, caspase-8 antibodies are used to pull down the respective complex. However, the method cannot discriminate whether this complex triggers apoptosis (through the RIPK1 → FADD → caspase-8 activation pathway), necroptosis (through the RIPK1 → RIPK3 → MLKL activation pathway) or nondeath signaling. The actual signaling output (death or nondeath signaling) depends on the stoichiometry of the respective molecules as well as on the activity of FLIP, caspase-8, or other factors.

Structural and spectroscopic studies of some adducts of silver(i) halides with thiourea and N-ethyl substituted thioureas

Syntheses, single crystal X-ray structural and spectroscopic characterizations are described for a variety of adducts of silver halides with thiourea ('tu'), N-ethylthiourea ('ettu' = EtNH.CS.NH(2)) and N,N'-diethylthiourea ('detu' = EtNH.CS.EtNH). This study greatly extends our knowledge of the complex chemistry of silver(i) halides with tu. The unexpected diversity of composition of such complexes was initially revealed by the powerful mechanochemical/IR method and the structures of several of the new complexes were determined by X-ray crystallographic studies of samples subsequently prepared from aqueous solution. Structural characterizations provide extensive geometrical data for (mononuclear 1 : 3) [XAg(xtu)(3)] arrays (xtu = ettu, detu; X = Cl, Br, I), assisting vibrational spectroscopic assignments. With the parent tu ligand, binuclear ionic forms are obtained: [tu(2)Ag(mu-tu)(2)Agtu(2)]X(2), the chloride as the dihydrate and the bromide as a di(thiourea) dihydrate adduct. With tu 1 : 2 complexes are defined for X = Cl, Br, as isomorphous one-dimensional polymers; AgCl:tu (1 : 1) is a two-dimensional net with six-membered Ag(3)S(3) rings and terminal chloride. Intermediate stoichiometries are defined in AgBr:tu (2 : 3), a one-dimensional polymer of Ag(2)S(2) rhombs linked at the silver atoms, while [Cl(2)Ag(3)(tu)(4)](NO(3)).H(2)O is also a one-dimensional polymer in which chloride and thiourea sulfur atoms link six-membered Ag(3)S(3) rings. Diagnostic bands in the IR and far-IR spectra of all of the synthesized complexes are assigned and interpreted in relation to the structures.

Effect of reaction components on the hydrolytic stability of tetrabutoxytitanium as the catalyst of benzanilide synthesis

Tetrabutoxytitanium reacts with vebzoic acid and benzanilide in o-xylene under reflux to form complexes resistant to water. Indirect evidence for the composition of such complexes was obtained by IR spectral analysis of their hydrolysis products. Under comparable conditions, tetrabutoxytitanium and its complexes with aniline, butanol, and butyl benzoate undergo fast hydrolysis yielding hydrated titanium oxide that precipitates. In the reaction of benzoic acid with aniline, catalyzed by tetrabutoxytitaniumom, the latter, forming complexes with benzoic acid and benzanilide, is not prone to hydrolysis and changing its catalytic activity due to reaction with the liberated water.

Fluorescent Proteins as Proteomic Probes

Protein complexes mediate the majority of cellular processes. Knowledge of the localization and composition of such complexes provides key insights into their functions. Although green fluorescent protein (GFP) has been widely applied for in vivo visualization of proteins, it has been relatively little used as a tool for the isolation of protein complexes. Here we describe the use of the standard GFP tag to both visualize proteins in living cells and capture their interactions via a simple immunoaffinity purification procedure. We applied this method to the analysis of a variety of endogenous protein complexes from different eukaryotic cells. We show that efficient isolations can be achieved in 5-60 min. This rapid purification helps preserve protein complexes close to their original state in the cell and minimizes nonspecific interactions. Given the wide use and availability of GFP-tagged protein reagents, the present method should greatly facilitate the elucidation of many cellular processes.

Na/K-ATPase Tethers Phospholipase C and IP3 Receptor into a Calcium-regulatory Complex

We have shown that the caveolar Na/K-ATPase transmits ouabain signals via multiple signalplexes. To obtain the information on the composition of such complexes, we separated the Na/K-ATPase from the outer medulla of rat kidney into two different fractions by detergent treatment and density gradient centrifugation. Analysis of the light fraction indicated that both PLC-gamma1 and IP3 receptors (isoforms 2 and 3, IP3R2 and IP3R3) were coenriched with the Na/K-ATPase, caveolin-1 and Src. GST pulldown assays revealed that the central loop of the Na/K-ATPase alpha1 subunit interacts with PLC-gamma1, whereas the N-terminus binds IP3R2 and IP3R3, suggesting that the signaling Na/K-ATPase may tether PLC-gamma1 and IP3 receptors together to form a Ca(2+)-regulatory complex. This notion is supported by the following findings. First, both PLC-gamma1 and IP3R2 coimmunoprecipitated with the Na/K-ATPase and ouabain increased this interaction in a dose- and time-dependent manner in LLC-PK1 cells. Depletion of cholesterol abolished the effects of ouabain on this interaction. Second, ouabain induced phosphorylation of PLC-gamma1 at Tyr(783) and activated PLC-gamma1 in a Src-dependent manner, resulting in increased hydrolysis of PIP2. It also stimulated Src-dependent tyrosine phosphorylation of the IP3R2. Finally, ouabain induced Ca(2+) release from the intracellular stores via the activation of IP3 receptors in LLC-PK1 cells. This effect required the ouabain-induced activation of PLC-gamma1. Inhibition of Src or depletion of cholesterol also abolished the effect of ouabain on intracellular Ca(2+).

A GPC study of non-stoichiometric polyelectrolyte complexes

A method has been developed for studying the compositional heterogeneity of water-soluble interpolymer complexes formed by oppositely charged polyelectrolytes. The distribution of chemical composition of such complexes can be calculated from data obtained by gel permeation chromatography with two detectors: a differential refractometer and a photometer. Polyelectrolyte complexes prepared from the sodium salt of poly(methacrylic acid) and poly( N-ethyl-4-vinylpyridinium) bromide were studied.

Potentiation of the immune response to influenza virus surface antigens by their covalent binding with synthetic carrier polymer

The surface antigens of influenza virus, namely hemagglutinin (HA) and neuraminidase (NA), are the principal antigens which induce the formation of protective antibodies in the infected organs [11,14]. However, HA and NA isolated from virus, when present in existing subunit vaccines, are only weakly immunogenic and are incapable of inducing a sufficiently effective immune response. Accordingly the development of ways of enhancing the immunogenicity of these surface antigens is an important step in the creation of new effective influenza vaccines. In recent years research into the creation of artificial antigens of a fundamentally new type, based on obtaining complexes or conjugates of antigenic structures of different nature with synthetic artificial polyelectrolytes of assigned composition and structure, which have a marked immunostimulating action, has made considerable progress [1-6]. Weakly immunogenic antigens of varied origin, in the composition of such complexes, are converted into highly immunogenic preparations, exhibiting some properties of T-independent antigens [i], and inducing an optimal specific immune response irrespective of the animals' genotype.