Search results for "Matrix"
showing 10 items of 3205 documents
Studies on the fat body of oncopeltus fasciatus invaded by pseudomonas aeruginosa1
1977
A fatal disease in laboratory cultures of Oncopeltus fasciatus is caused by Pseudomonas aeruginosa , which invades the fat body and destroys it. The cellular breakdown was studied by electron microscopy. Infected fat body tissue shrinks, disintegrates, and dissolves. The nuclei, apparently, remain intact until immediately before cell death. Bacteria, which are found singularly in cytoplasm, form an expanding electron-lucent halo. Within this halo, free ribosomes and ribosomes of rough endoplasmic reticulum (ER) disappear. The changes are presumably caused by proteolytic activity of the parasite, which results in the destruction of the fat body and death of the host. Lipid droplets dissolve,…
Local spectral theory for Drazin invertible operators
2016
Abstract In this paper we investigate the transmission of some local spectral properties from a bounded linear operator R, as SVEP, Dunford property (C), and property (β), to its Drazin inverse S, when this does exist.
Meprins process matrix metalloproteinase-9 (MMP-9)/gelatinase B and enhance the activation kinetics by MMP-3
2012
Abstract Meprin α and β, members of the astacin family of zinc metalloproteinases, are unique plasma membrane and secreted proteases known to cleave a wide range of biological substrates involved in inflammation, cancer and fibrosis. In this study, we identified proMMP-9 as a novel substrate and show that aminoterminal meprin-mediated clipping improves the activation kinetics of proMMP-9 by MMP-3, an efficient activator of proMMP-9. Interestingly, the NH2-terminus LVLFPGDL, generated by incubation with meprin α, is identical to the form produced in conditioned media from human neutrophils and monocytes. Hence, this meprin-mediated processing and enhancement of MMP-9 activation kinetics may …
Specific processing of tenascin-C by the metalloprotease meprinβ neutralizes its inhibition of cell spreading
2009
The metalloprotease meprin has been implicated in tissue remodelling due to its capability to degrade extracellular matrix components. Here, we investigated the susceptibility of tenascin-C to cleavage by meprinbeta and the functional properties of its proteolytic fragments. A set of monoclonal antibodies against chicken and human tenascin-C allowed the mapping of proteolytic fragments generated by meprinbeta. In chicken tenascin-C, meprinbeta processed all three major splicing variants by removal of 10kDa N-terminal and 38kDa C-terminal peptides, leaving a large central part of subunits intact. A similar cleavage pattern was found for large human tenascin-C variant where two N-terminal pep…
Efficient computation of root mean square deviations under rigid transformations
2013
The computation of root mean square deviations (RMSD) is an important step in many bioinformatics applications. If approached naively, each RMSD computation takes time linear in the number of atoms. In addition, a careful implementation is required to achieve numerical stability, which further increases runtimes. In practice, the structural variations under consideration are often induced by rigid transformations of the protein, or are at least dominated by a rigid component. In this work, we show how RMSD values resulting from rigid transformations can be computed in constant time from the protein's covariance matrix, which can be precomputed in linear time. As a typical application scenar…
Bishistidyl heme hexacoordination, a key structural property in Drosophila melanogaster hemoglobin
2005
Hemoglobins at high concentration have been isolated long ago from some insect larvae living in hypoxic environments. Conversely, a monomeric hemoglobin has been discovered recently in the fruit fly Drosophila melanogaster as intracellular protein expressed both in larvae and in the adult fly. Such a finding indicates that the oxygen supply in insects may be more complex than previously thought, relying not only on O2 diffusion through the tubular tracheal system, but also on carrier-mediated transport and storage. We present here the crystal structure of recombinant D. melanogaster hemoglobin at 1.20 A resolution. Spectroscopic data show that the protein displays a hexacoordinated heme, wh…
Protein Thermal Denaturation and Matrix Glass Transition in Different Protein−Trehalose−Water Systems
2011
Biopreservation by saccharides is a widely studied issue due to its scientific and technological importance; in particular, ternary amorphous protein-saccharide-water systems are extensively exploited to model the characteristics of the in vivo biopreservation process. We present here a differential scanning calorimetry (DSC) study on amorphous trehalose-water systems with embedded different proteins (myoglobin, lysozyme, BSA, hemoglobin), which differ for charge, surface, and volume properties. In our study, the protein/trehalose molar ratio is kept constant at 1/40, while the water/sugar molar ratio is varied between 2 and 300; results are compared with those obtained for binary trehalose…
Proteome-Wide Characterization of the RNA-Binding Protein RALY-Interactome Using the in Vivo-Biotinylation-Pulldown-Quant (iBioPQ) Approach
2013
RALY is a member of the heterogeneous nuclear ribonucleoproteins, a family of RNA-binding proteins generally involved in many processes of mRNA metabolism. No quantitative proteomic analysis of RALY-containing ribonucleoparticles (RNPs) has been performed so far, and the biological role of RALY remains elusive. Here, we present a workflow for the characterization of RALY's interaction partners, termed iBioPQ, that involves in vivo biotinylation of biotin acceptor peptide (BAP)-fused protein in the presence of the prokaryotic biotin holoenzyme synthetase of BirA so that it can be purified using streptavidin-coated magnetic beads, circumventing the need for specific antibodies and providing e…
Evolution of nacre: biochemistry and proteomics of the shell organic matrix of the cephalopod Nautilus macromphalus.
2009
12 pages; International audience; In mollusks, one of the most widely studied shell textures is nacre, the lustrous aragonitic layer that constitutes the internal components of the shells of several bivalves, a few gastropods, and one cephalopod: the nautilus. Nacre contains a minor organic fraction, which displays a wide range of functions in relation to the biomineralization process. Here, we have biochemically characterized the nacre matrix of the cephalopod Nautilus macromphalus. The acid-soluble matrix contains a mixture of polydisperse and discrete proteins and glycoproteins, which interact with the formation of calcite crystals. In addition, a few bind calcium ions. Furthermore, we h…
Metaproteomic analysis of atmospheric aerosol samples.
2016
Metaproteomic analysis of air particulate matter provides information about the abundance and properties of bioaerosols in the atmosphere and their influence on climate and public health. We developed and applied efficient methods for the extraction and analysis of proteins from glass fiber filter samples of total, coarse, and fine particulate matter. Size exclusion chromatography was applied to remove matrix components, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was applied for protein fractionation according to molecular size, followed by in-gel digestion and LC-MS/MS analysis of peptides using a hybrid Quadrupole-Orbitrap MS. Maxquant software and the Swiss-…