scholarly journals N-terminal stretch Arg2, Arg3, Arg4 and Arg5 of human lactoferrin is essential for binding to heparin, bacterial lipopolysaccharide, human lysozyme and DNA

1997 ◽  
Vol 328 (1) ◽  
pp. 145-151 ◽  
Author(s):  
Patrick H. C. VAN BERKEL ◽  
E. J. Marlieke GEERTS ◽  
A. Harry VAN VEEN ◽  
Mathias MERICSKAY ◽  
A. Herman DE BOER ◽  
...  
Keyword(s):  
Lipid A ◽  
Solid Phase ◽  
Decisive Role ◽  
Bacterial Lipopolysaccharide ◽  
Human Lactoferrin ◽  
Binding Assays ◽  
Human Lysozyme ◽  
Ligand Interaction ◽  
Arginine Residues

Human lactoferrin (hLF), a protein involved in host defence against infection and excessive inflammation, interacts with heparin, the lipid A moiety of bacterial lipopolysaccharide, human lysozyme (hLZ) and DNA. To determine which region of the molecule is important in these interactions, solid-phase ligand binding assays were performed with hLF from human milk (natural hLF) and N-terminally deleted hLF variants. Iron-saturated and natural hLF bound equally well to heparin, lipid A, hLZ and DNA. Natural hLF lacking the first two N-terminal amino acids (Gly1-Arg2) showed reactivities of one-half, two-thirds, one-third and one-third towards heparin, lipid A, hLZ and DNA respectively compared with N-terminally intact hLF. A lack of the first three residues (Gly1-Arg2-Arg3) decreased binding to the same ligands to one-eighth, one-quarter, one-twentieth and one-seventeenth respectively. No binding occurred with a mutant lacking the first five residues (Gly1-Arg2-Arg3-Arg4-Arg5). An anti-hLF monoclonal antibody (E11) that reacts to an N-lobe epitope including Arg5 completely blocked hLF-ligand interaction. These results show that the N-terminal stretch of four consecutive arginine residues, Arg2-Arg3-Arg4-Arg5, has a decisive role in the interaction of hLF with heparin, lipid A, hLZ and DNA. The role of limited N-terminal proteolysis of hLF in its anti-infective and anti-inflammatory properties is discussed.

Nuclear Radiation Detection Scintillators based on ZnSe(Te) crystals.

2011 ◽  
Vol 1341 ◽  
Author(s):  
Volodymyr D. Ryzhikov
Keyword(s):  
Solid Phase ◽  
Radiation Detection ◽  
Decisive Role ◽  
Nuclear Radiation ◽  
Energy Devices ◽  
Preparation Conditions ◽  
Radiation Spectra ◽  
Scintillation Crystals ◽  
Kinetics Of

ABSTRACTWe describe development of semiconductor scintillators (SCS) on the basis of AIIBVI compounds has bridged the gap in a series of “scintillator-photodiode” detectors used in modern multi-channel low-energy devices for visualization of hidden images (tomographs, introscopes). In accordance with the requirements of eventual applications, such SCS materials as ZnSe(Te) show the best matching of intrinsic radiation spectra to photosensitivity spectra of silicon photodiodes (PD) among the materials of similar kind. They are characterized by high radiation and thermal stability of their output parameters, as well as by high conversion efficiency. In this work, a thermodynamic model is described for interaction of isovalent dopants (IVD) with intrinsic point defects of AIIBVI semiconductor structures at different ratios of their charges, a decisive role of IVD is shown in formation of the luminescence centers, kinetics of solid-phase reactions and the role of a gas medium are considered under real preparation conditions of ZnSe(Te) scintillation crystals, and luminescence mechanisms in IVD-doped SCS are discussed.

scholarly journals Glycosylated and unglycosylated human lactoferrins both bind iron and show identical affinities towards human lysozyme and bacterial lipopolysaccharide, but differ in their susceptibilities towards tryptic proteolysis

1995 ◽  
Vol 312 (1) ◽  
pp. 107-114 ◽  
Author(s):  
P H C van Berkel ◽  
M E J Geerts ◽  
H A van Veen ◽  
P M Kooiman ◽  
F R Pieper ◽  
...  
Keyword(s):  
Human Kidney ◽  
Exchange Chromatography ◽  
Protein Sequencing ◽  
Bacterial Lipopolysaccharide ◽  
Terminal Sequence ◽  
Human Lysozyme ◽  
Major Function ◽  
Sds Page ◽  
Anti Inflammatory

We studied the role of N-glycosylation of human lactoferrin (hLF) with respect to properties that are relevant to its antibacterial and anti-inflammatory activities. A human kidney-derived 293(S) cell line that constitutively expresses recombinant hLF (rhLF) was produced. The reactivity towards various antibodies of rhLF that had been expressed in the absence or presence of tunicamycin (which blocks N-linked glycosylation) did not differ from that of natural (human milk-derived) hLF. Cation-exchange chromatography and N-terminal protein sequencing showed identical cationic properties and an intact N-terminal sequence for rhLF and natural hLF. SDS/PAGE of rhLF expressed in the presence of tunicamycin revealed a protein with the same M(r) as that of enzymically deglycosylated natural hLF. Both glycosylated and unglycosylated rhLF appeared to be completely saturated with iron. The affinity of natural hLF, glycosylated and non-glycosylated rhLF for both human lysozyme (Kd 4.5 x 10(-8) M) and bacterial lipopolysaccharide did not differ. SDS/PAGE of hLF species subjected to trypsin indicated that unglycosylated rhLF was much more susceptible to degradation. Furthermore, this analysis suggests that N-glycosylation heterogeneity in natural hLF and rhLF resides in the C-lobe. Thus our results provide no argument for differential antibacterial and/or anti-inflammatory activity of natural and (glycosylated) rhLF and suggest that a major function of glycosylation in hLF is to protect it against proteolysis.

Role of a PDZ1 domain of NHERF1 in the binding of airway epithelial RACK1 to NHERF1

2004 ◽  
Vol 286 (5) ◽  
pp. C1037-C1044 ◽  
Author(s):  
Carole M. Liedtke ◽  
Viswanathan Raghuram ◽  
C. Chris Yun ◽  
Xiangyun Wang
Keyword(s):  
Amino Acid ◽  
Solid Phase ◽  
Binding Constants ◽  
Dependent Manner ◽  
Airway Epithelial ◽  
Binding Assays ◽  
Glutathione S Transferase ◽  
Cell Lysate ◽  
A Site

In past studies, we demonstrated regulation of CFTR Cl channel function by protein kinase C (PKC)-ϵ through the binding of PKC-ϵ to RACK1 (a receptor for activated C-kinase) and of RACK1 to human Na+/H+ exchanger regulatory factor (NHERF1). In this study, we investigated the site of RACK1 binding on NHERF1 using solid-phase and solution binding assays and pulldown, immunoprecipitation, and 36Cl efflux experiments. Recombinant RACK1 binding to glutathione S-transferase (GST)-tagged PDZ1 domain of NHERF1 was 10-fold higher than its binding to GST-tagged PDZ2 domain of NHERF1. PDZ1 binds to RACK1 in a dose-dependent manner and vice versa, with similar binding constants of 1.67 and 1.26 μg, respectively. Interaction of the PDZ1 domain with RACK1 was not blocked by binding of activated PKC-ϵ to RACK1. A GST-tagged PDZ1 domain pulled down endogenous RACK1 from Calu-3 cell lysate. An internal 11-amino acid motif embedding the GYGF carboxylate binding loop of PDZ1 binds to RACK1, inhibits binding of recombinant NHERF1 and RACK1, pulls down endogenous RACK1 from Calu-3 cell lysate, and blocks coimmunoprecipitation of endogenous RACK1 with endogenous NHERF1 but does not affect cAMP-dependent activation of CFTR. A similar amino acid sequence in the PDZ2 domain did not bind RACK1. Our results indicate binding of Calu-3 RACK1 predominantly to the PDZ1 domain of NHERF1 at a site encompassing the GYGF loop of the PDZ1 domain and a site on RACK1 distinct from a PKC-ϵ binding site. CFTR activation by cAMP-generating agent is not affected by loss of RACK1-NHERF1 interaction.

The main directions of educational policy of Finland

2020 ◽  
Vol 11 (2) ◽  
pp. 6-13
Author(s):  
K. E. Stupak ◽  
Keyword(s):  
Higher Education ◽  
Education Policy ◽  
Education System ◽  
Decisive Role ◽  
The State ◽  
Vocational Education And Training ◽  
State Education Policy ◽  
Role Of The State ◽  
State Education

The article deals with analyzing the main streams of the education policy in Finland, which reflect the relationship between a person and society in modern socio–economic conditions. Such policy directs the system of education to change the person and his mind himself. Finland using its education system, has long before been concerned about preparing people for the future by reforming approaches to teaching in schools and higher education institutions. As a result, it has achieved world–wide recognition and top positions in various ratings have resulted. Therefore, today there is a great interest of scientists in certain issues of education functioning in Finland. Thus, G. Androshchuk, V. Butova. I. Zhernokleeva, T. Pushkareva and others study in their works the purpose and decisive role of Finland's education policy in the development of the education system. S. Grinyuk and V. Zagvozdkin pay attention to the practical the steps of reforming the Finnish system of education. T. Drobyshevsk investigates the system of providing educational services in Finland as a sector of knowledge production. L. Volynets, P. Kukharchuk consider the principles of the state education policy of Finland. L. Smolskaya examines the role of the state policy in implementing the "Finnish phenomenon"; P. Basyliuk and Yu. Kulykova, focus attention on the study of the evolution of the system of higher education in Finland; O. Scherbak reveals peculiarities of vocational education and training.

Democratization in Serbia: An Analysis of Rational Choice and Structuralist Explanations

2015 ◽  
Author(s):  
Dunja Apostolov-Dimitrijevic
Keyword(s):  
Rational Choice ◽  
Path Dependence ◽  
Theoretical Perspective ◽  
Political Leadership ◽  
Decisive Role ◽  
The Other ◽  
Internal Factors ◽  
Transitional Societies ◽  
The Face

This paper explains political democratization in Post-Milosevic Serbia, utilizing two different accounts of the democratization process: one rooted in the rational choice framework and the other in structuralism. While rational choice explains the decisive role of political leadership in overcoming path dependence, the structuralist explanations show the transnational linkages that encourage democratization in the face of domestic setbacks. This particular debate between the two types of explanations represents the larger debate concerning the role of internal factors and external linkages in propelling democratization in transitional societies. The paper concludes by integrating the two sets of explanations offered by each theoretical perspective, in order to develop a coherent understanding of Serbia's democratization.   Full text available at: https://doi.org/10.22215/rera.v9i1.240

Identification of a Coronavirus Hemagglutinin-Esterase with a Substrate Specificity Different from Those of Influenza C Virus and Bovine Coronavirus

1999 ◽  
Vol 73 (5) ◽  
pp. 3737-3743 ◽  
Author(s):  
Alfred Klausegger ◽  
Birgit Strobl ◽  
Gerhard Regl ◽  
Alexandra Kaser ◽  
Willem Luytjes ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Solid Phase ◽  
Hepatitis Virus ◽  
Bovine Brain ◽  
Brain Extract ◽  
Binding Assays ◽  
Bovine Coronavirus ◽  
Close Relationship ◽  
Influenza C Virus ◽  
Cloned Gene

ABSTRACT We have characterized the hemagglutinin-esterase (HE) of puffinosis virus (PV), a coronavirus closely related to mouse hepatitis virus (MHV). Analysis of the cloned gene revealed approximately 85% sequence identity to HE proteins of MHV and approximately 60% identity to the corresponding esterase of bovine coronavirus. The HE protein exhibited acetylesterase activity with synthetic substratesp-nitrophenyl acetate, α-naphthyl acetate, and 4-methylumbelliferyl acetate. In contrast to other viral esterases, no activity was detectable with natural substrates containing 9-O-acetylated sialic acids. Furthermore, PV esterase was unable to remove influenza C virus receptors from human erythrocytes, indicating a substrate specificity different from HEs of influenza C virus and bovine coronavirus. Solid-phase binding assays revealed that purified PV was unable to bind to sialic acid-containing glycoconjugates like bovine submaxillary mucin, mouse α1macroglobulin or bovine brain extract. Because of the close relationship to MHV, possible implications on the substrate specificity of MHV esterases are suggested.

Introduction to geomicrobiology

2018 ◽  
Author(s):  
David L. Kirchman
Keyword(s):  
Fossil Fuels ◽  
Solid Phase ◽  
Direct Reduction ◽  
Iron Oxidation ◽  
Mineral Dissolution ◽  
Precipitation Process ◽  
Soluble Ions ◽  
Chemolithoautotrophic Bacteria ◽  
The Impact

Geomicrobiology, the marriage of geology and microbiology, is about the impact of microbes on Earth materials in terrestrial systems and sediments. Many geomicrobiological processes occur over long timescales. Even the slow growth and low activity of microbes, however, have big effects when added up over millennia. After reviewing the basics of bacteria–surface interactions, the chapter moves on to discussing biomineralization, which is the microbially mediated formation of solid minerals from soluble ions. The role of microbes can vary from merely providing passive surfaces for mineral formation, to active control of the entire precipitation process. The formation of carbonate-containing minerals by coccolithophorids and other marine organisms is especially important because of the role of these minerals in the carbon cycle. Iron minerals can be formed by chemolithoautotrophic bacteria, which gain a small amount of energy from iron oxidation. Similarly, manganese-rich minerals are formed during manganese oxidation, although how this reaction benefits microbes is unclear. These minerals and others give geologists and geomicrobiologists clues about early life on Earth. In addition to forming minerals, microbes help to dissolve them, a process called weathering. Microbes contribute to weathering and mineral dissolution through several mechanisms: production of protons (acidity) or hydroxides that dissolve minerals; production of ligands that chelate metals in minerals thereby breaking up the solid phase; and direct reduction of mineral-bound metals to more soluble forms. The chapter ends with some comments about the role of microbes in degrading oil and other fossil fuels.

Ability of PknA, a mycobacterial eukaryotic-type serine/threonine kinase, to transphosphorylate MurD, a ligase involved in the process of peptidoglycan biosynthesis

2008 ◽  
Vol 415 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Meghna Thakur ◽  
Pradip K. Chakraborti
Keyword(s):  
Protein Kinases ◽  
Solid Phase ◽  
Morphological Changes ◽  
Binding Assays ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Peptidoglycan Biosynthesis ◽  
Vitro Binding ◽  
Solid Phase Binding

Eukaryotic-type serine/threonine protein kinases in bacteria have been implicated in controlling a host of cellular activities. PknA is one of eleven such protein kinases from Mycobacterium tuberculosis which regulates morphological changes associated with cell division. In the present study we provide the evidence for the ability of PknA to transphosphorylate mMurD (mycobacterial UDP-N-acetylmuramoyl-L-alanine:D-glutamate-ligase), the enzyme involved in peptidoglycan biosynthesis. Its co-expression in Escherichia coli along with PknA resulted in phosphorylation of mMurD. Consistent with these observations, results of the solid-phase binding assays revealed a high-affinity in vitro binding between the two proteins. Furthermore, overexpression of m-murD in Mycobacterium smegmatis yielded a phosphorylated protein. The results of the present study therefore point towards the possibility of mMurD being a substrate of PknA.

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