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81.
Amelioration of chronic murine colitis by peptide-mediated transduction of the IkappaB kinase inhibitor NEMO binding domain peptide 总被引:1,自引:0,他引:1
82.
In bacteria, the SecYEG protein translocation complex employs the cytosolic ATPase SecA to couple the energy of ATP binding and hydrolysis to the mechanical force required to push polypeptides through the membrane. The molecular basis of this energy transducing reaction is not well understood. A peptide-binding array has been employed to identify sites on SecYEG that interact with SecA. These results along with fluorescence spectroscopy have been exploited to characterise a long-distance conformational change that connects the nucleotide-binding fold of SecA to the transmembrane polypeptide channel in SecY. These movements are driven by binding of non-hydrolysable ATP analogues to a monomer of SecA in association with the SecYEG complex. We also determine that interaction with SecYEG simultaneously decreases the affinity of SecA for ATP and inhibitory magnesium, favouring a previously identified active state of the ATPase. Mutants of SecA capable of binding but not hydrolysing ATP do not elicit this conformationally active state, implicating residues of the Walker B motif in the early chain of events that couple ATP binding to the mobility of the channel. 相似文献
83.
Borna disease virus matrix protein is an integral component of the viral ribonucleoprotein complex that does not interfere with polymerase activity 下载免费PDF全文
Chase G Mayer D Hildebrand A Frank R Hayashi Y Tomonaga K Schwemmle M 《Journal of virology》2007,81(2):743-749
We have recently shown that the matrix protein M of Borna disease virus (BDV) copurifies with the affinity-purified nucleoprotein (N) from BDV-infected cells, suggesting that M is an integral component of the viral ribonucleoprotein complex (RNP). However, further studies were hampered by the lack of appropriate tools. Here we generated an M-specific rabbit polyclonal antiserum to investigate the intracellular distribution of M as well as its colocalization with other viral proteins in BDV-infected cells. Immunofluorescence analysis revealed that M is located both in the cytoplasm and in nuclear punctate structures typical for BDV infection. Colocalization studies indicated an association of M with nucleocapsid proteins in these nuclear punctate structures. In situ hybridization analysis revealed that M also colocalizes with the viral genome, implying that M associates directly with viral RNPs. Biochemical studies demonstrated that M binds specifically to the phosphoprotein P but not to N. Binding of M to P involves the N terminus of P and is independent of the ability of P to oligomerize. Surprisingly, despite P-M complex formation, BDV polymerase activity was not inhibited but rather slightly elevated by M, as revealed in a minireplicon assay. Thus, unlike M proteins of other negative-strand RNA viruses, BDV-M seems to be an integral component of the RNPs without interfering with the viral polymerase activity. We propose that this unique feature of BDV-M is a prerequisite for the establishment of BDV persistence. 相似文献
84.
Moreira MR Kanashiro A Kabeya LM Polizello AC Azzolini AE Curti C Oliveira CA T-do Amaral A Lucisano-Valim YM 《Life sciences》2007,81(4):317-326
Tissue damage in autoimmune diseases involves excessive production of reactive oxygen species (ROS) triggered by immune complexes (IC) and neutrophil (PMN) interactions via receptors for the Fc portion of IgG (FcgammaR) and complement receptors (CR). Modulation of both the effector potential of these receptors and ROS generation may be relevant to the maintenance of body homeostasis. In the present study, the modulatory effect of four flavonols (myricetin, quercetin, kaempferol, galangin) on rabbit PMN oxidative metabolism, specifically stimulated via FcgammaR, CR or both classes of receptors, was evaluated by luminol- and lucigenin-dependent chemiluminescence assays. Results showed that flavonol inhibitory effect was not dependent on the cell membrane receptor class stimulated but related to the lipophilicity of the compounds (their apparent partition coefficient values were obtained by high-performance liquid chromatography), and was also inversely related to the number of hydroxyl groups in the flavonol B ring and the ROS-scavenger activity (assessed by the luminol--H2O2--horseradish peroxidase reaction). Under the experimental conditions the flavonols tested were not toxic to PMNs (evaluated by lactate dehydrogenase release and trypan blue exclusion) and did not interfere with IC-induced phagocytosis (evaluated by transmission electron microscopy). Our results suggested that inhibition of IC-stimulated PMNs effector functions by the flavonols tested herein was the result of cooperation of different cellular mechanisms. 相似文献
85.
86.
Ferrer B Bermúdez-Silva FJ Bilbao A Alvarez-Jaimes L Sanchez-Vera I Giuffrida A Serrano A Baixeras E Khaturia S Navarro M Parsons LH Piomelli D Rodríguez de Fonseca F 《The Biochemical journal》2007,408(1):97-104
FgFtr1 and FgFtr2 are putative iron permeases, and FgFet1 and FgFet2 are putative ferroxidases of Fusarium graminearum. They have high homologies with iron permease ScFtr1 and ferroxidase ScFet3 of Saccharomyces cerevisiae at the amino acid level. The genes encoding iron permease and ferroxidase were localized to the same chromosome in the manner of FgFtr1/FgFet1 and FgFtr2/FgFet2. The GFP (green fluorescent protein)-fused versions of FgFtr1 and FgFtr2 showed normal functions when compared with FgFtr1 and FgFtr2 in an S. cerevisiae system, and the cellular localizations of FgFtr1 and FgFtr2 in S. cerevisiae depended on the expression of their putative ferroxidase partners FgFet1 and FgFet2 respectively. Although FgFtr1 was found on the plasma membrane when FgFet1 and FgFtr1 were co-transformed in S. cerevisiae, most of the FgFtr1 was found in the endoplasmic reticulum compartment when co-expressed with FgFet2. Furthermore, FgFtr2 was found on the vacuolar membrane when FgFet2 was co-expressed. From the two-hybrid analysis, we confirmed the interaction of FgFtr1 and FgFet1, and the same result was found between FgFtr2 and FgFet2. Iron-uptake activity also depended on the existence of the respective partner. Finally, the FgFtr1 and FgFtr2 were found on the plasma and vacuolar membrane respectively, in F. graminearum. Taken together, these results strongly suggest that FgFtr1 and FgFtr2 from F. graminearum encode the iron permeases of the plasma membrane and vacuolar membrane respectively, and require their specific ferroxidases to carry out normal function. Furthermore, the present study suggests that the reductive iron-uptake system is conserved from yeast to filamentous fungi. 相似文献
87.
88.
New data suggest that even children with autism are subject to race and gender stereotypes. This result constrains theories of stereotype acquisition and social cognition in autism. 相似文献
89.
90.
Letterio Guglielmo Giacomo Zagami Vincenzo Saggiomo Giulio Catalano Antonia Granata 《Polar Biology》2007,30(6):747-758
The aim of this study was to investigate patterns of abundance, distribution, temporal changes and species composition of
the dominant ice-associated copepods in the spring annual pack ice, platelet ice and water column at Terra Nova Bay, Ross
Sea, during late spring 1997. Ice cores were drilled for temporal and spatial scales. Stephos longipes and Harpacticus furcifer dominated the sea ice meiofauna in terms of numbers in the lower few centimeters of the bottom ice associated with high chlorophyll
a and phaeopigment levels. Nauplii dominated the S. longipes population (91.6%) and occurred in extremely high concentrations. In contrast, copepodids were the dominant stages in H. furcifer. How H. furcifer carries out its entire life cycle and how it differs from ecologically similar species such as Drescheriella glacialis should be examined in more detail. 相似文献