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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Electron spin resonance (ESR) spectra of the spin probes C5 and C16, the iminoxyl derivatives of stearic acids, have been investigated after their incorporation into lipid membranes of influenza and Sendai viruses. At room temperature the spectra of both probes coincided indicating the similar composition and origin of lipid viral membranes. Similar to influenza virus, Sendai virus was shown to possess the external lipid bilayer. Investigation of the rigidity of the lipid phase of myxoviruses as a function temperature has shown that the structure of the lipid external layer (no less than 8 A in thickness) is due to surface glycoproteins incorporated into the viral membrane. The structural transition of the lipid phase of influenza and Sendai viruses 8 A apart from the viral surface was observed at 50 degrees C. The surface glycoproteins do not probably penetrate deep in the lipid membrane of myxoviruses and do not condition its structure at long distances (22 A) from the viral surface. The completely reversible structural transition of lipid phase at this distance was observed at temperatures 17--20 degrees C.
Mol Biol (Mosk)
PMID:[Investigation of myxovirus structure by spin probes. I. Thermostability of the lipid membrane of influenza and Sendai viruses]. 22 31

The lipid membrane structure of two myxoviruses (influenza and Sendai viruses), red blood cells and liposomes (prepared from total lipids of Sendai virus) have been investigated in the presence of rimantadine by means of two spin probes C5 and C6--the iminoxyl derivatives of stearic acids. Rimantadine was shown to penetrate the lipid membranes of myxoviruses and red blood sells and change the structure of the lipid phase no less than 0.8 nm apart from the viral surface. In the depth of 2.2 nm the structure of these lipid membranes remains unchanged after addition of rimantadine. Rimantadine also displaces the phase transition points of cell and viral lipid membranes to lower temperatures. Rimantadine does not change the lipid bilayer structure of liposomes 0.8 nm apart from its surface. These finding allow to suggest that rimantadine affects the cell and viral lipoprotein membranes.
Mol Biol (Mosk)
PMID:[Myxovirus structural investigations by spin probe methods. II. Influence of rimantadine on the structure of viral and artificial lipid membranes]. 22 79

Large amounts of RNA and RNP isolated from influenza virus were obtained. This has allowed us to undertake detailed physical studies of the secondary structure of RNA of influenza virus in free form and in RNP. Analysis of CD spectrum and the hypochromic effect after thermal denaturation of RNA indicated that RNA in free form contains 58--62% double-stranded regions. By comparative studies of the secondary structure of RNA in RNP, it was estimated that 12--14% of the RNA exists in double-stranded form.
Mol Biol (Mosk)
PMID:[Secondary structure of RNA of influenza virus in free form and in ribonucleoprotein]. 46 Feb 7

After polyadenylation in vitro of the influenza virus RNA segment which contains the coding information for the matrix protein, a cDNA copy can be made using the primer p(dT)8-dA and reverse transcriptase. The sequence of 166 nucleotides of the cDNA was determined by a modification [Brownlee, G. G. & Cartwright, E. M. (1977) J. Mol. Biol, 114, 93--117] of the plus/minus method [Sanger, F. & Coulson, A. R. (1975) J. Mol. Biol. 94, 441--481] and adaptation of the "dideoxy" method [Sanger, F., Nicklen, S. & Coulson, A. R. (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 5463--5467] for sequencing DNA. The cDNA sequences is of the same sense as the mRNA for matrix protein and contains a potential initiating codon, d(ATG), at position 26--28. When matrix protein purified from virus particles was digested with chymotrypsin or trypsin and the amino acid compositions of separated peptides determined, one peptide containing nine amino acids found which had a composition corresponding to that predicted by the cDNA sequence following the first methionine codon, confirming that protein synthesis initiates at this position. The compositions of four other peptides matches those predicted from the nucleotide sequence. There is no processing of the N terminus of the protein before incorporation into the virus particle except for removal of the N-terminal methionine and addition of a "blocking" group on the resulting N-terminal serine residue.
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PMID:Nucleotide sequence coding for the N-terminal region of the matrix protein influenza virus. 57 97

The intracellular influenza virus-containing structures involved in RNA synthesis in the cytoplasm and in the nucleoplasm of infected chicken fibroblasts were studied. Two approaches were used: (1) short pulse labeling of infected cell with [3H]uridine; (2) determination in vitro of polymerase activity of intracellular virus-specific structures. Both methods revealed functionally active virus-specific structures in the nucleoplasm and showed that a functionally active virus-specific structure was localized in the nucleoplasm of infected cells. This structure contained proteins of the viral ribonucleoprotein, but sedimented somewhat faster (at 60--90S in velocity sucrose and glycerol gradients). Meanwhile, polymerase-containing structures in the cytoplasm of infected cells sedimented in the position of viral ribonucleoproteins (25--60S).
Mol Biol (Mosk)
PMID:[Intracellular structures of influenza virus]. 65 75

A mechanism responsible for proteolytic deproteinization of influenza virus A2 Hong-Kong (I)68 by plasmatic membranes of sensitive cells was studied. Presence of trypsinlike protease in plasmatic membranes of white mice lungs was demonstrated. A considerable inhibition of the membrane proteolitic activity was obtained in the presence of epsilon-aminocaproic acid. Disintegration of the virus labeled by [3H]uridine by plasmatic membranes was investigated and it was found that this process required ATP. Inhibition of the protease activity by epsilon-aminocaproic acid led to the suppression of deproteinization of influenza virus. The experimental data obtained indicate that the proteolytic enzymes of plasmatic membranes participate in the complex process of virus "uncoating".
Mol Biol (Mosk)
PMID:[Proteolytic mechanism of deproteinization of influenza virus by plasmatic membranes]. 75 90

The sialidase from Salmonella typhimurium LT2 was characterized by using photoaffinity-labelling techniques. The well-known sialidase inhibitor 5-acetamido-2,6-anhydro-3,5-dideoxy-D-glycero-D-galacto-non- 2-enonic acid (Neu5Ac2en) was modified to contain an amino group at C-9, which permitted the incorporation of 4-azidosalicylic acid in amide linkage at this position. Labelling of the purified protein with the radioactive (125I) photoprobe was determined to be highly specific for a region within the active-site cavity. This conclusion was based on the observation that the competitive inhibitor Neu5Ac2en in the photolysis mixture prevented labelling of the protein. In contrast, compounds with structural and chemical features similar to the probe and Neu5Ac2en, but which were not competitive enzyme inhibitors, did not affect the photolabelling of the protein. The peptide interacting with the probe was identified by CNBr treatment of the labelled protein, followed by N-terminal sequence analysis. Inspection of the primary structure of the protein, predicted from the cloned structural gene for the sialidase [Hoyer, Hamilton, Steenbergen & Vimr (1992) Mol. Microbiol. 6, 873-884] revealed that the label was incorporated into a 9.6 kDa fragment situated within the terminal third of the molecule near the C-terminal end. Secondary-structural predictions using the Garnier-Robson algorithm [Garnier, Osguthorpe & Robson (1978) J. Mol. Biol. 120, 97-120] of the labelled peptide revealed a structural similarity to the active site of influenza-A- and Sendai-HN-virus sialidases with a repetitive series of alternating beta-sheets connected with loops.
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PMID:Photolabelling of Salmonella typhimurium LT2 sialidase. Identification of a peptide with a predicted structural similarity to the active sites of influenza-virus sialidases. 129 92

To evaluate the effect of laboratory passaging of influenza virus A/USSR/90/77 (H1N1) on the pattern of vRNA synthesis regulation in course of the one step infection cycle, we have used the viral variants adapted to growth in the continuous cell line MDCK or to the reproduction in the mice lungs in vivo. Enhancement of regulation was registered in the adapted variants as compared to the original virus strain. The results are discussed in connection with possible significance of the vRNA synthesis regulation for the efficiency of viral reproduction under natural conditions or in laboratory passaging.
Mol Gen Mikrobiol Virusol
PMID:[Change in regulation of influenza virus vRNA synthesis during adaptation to various hosts]. 129 85

Mitogen-activated protein kinases (MAPKs) or extracellular signal-regulated kinases (ERKs) are serine/threonine kinases of apparent Mr 42-44 kDa that are rapidly activated by a variety of extracellular signals in many cell types. This activation coincides with their phosphorylation on tyrosine and threonine residues, and these covalent modifications are required for full activity of the enzymes. They are thought to play a pivotal role in integrating and transmitting transmembrane signals for growth and differentiation. Here, we report the cloning, sequence, and functional expression in fibroblasts of the hamster p44 MAP kinase (p44mapk). The protein deduced from the nucleotide sequence of an almost full-length cDNA is 98.6% homologous to the rat p44mapk (ERK1). To distinguish the expression of the cloned cDNA from the endogenous p44mapk, we fused to the 5' end of the cDNA an initiating codon followed by an influenza hemagglutinin 9-residue peptide epitope (HAP). The chimeric kinase HAP/p44mapk, under transcriptional control of the cytomegalovirus promoter, was stably expressed in Chinese hamster lung fibroblasts in a functional form. We show that its basal activity, measured by phosphorylation of the substrate myelin basic protein, is activated severalfold (up to 25) by the mitogens alpha-thrombin, platelet-derived growth factor, and fetal calf serum. In addition, we report that in response to alpha-thrombin, this activation is rapid (6-fold in 1 min), biphasic (first peak at 5 min, second broader peak at 1-2 h), persistent (for greater than or equal to 4 h), and parallel to an increased phosphorylation on tyrosine.We conclude that the constructed and stably expressed chimera, HAP/p44mapk, has retained apparently all the hormonal regulation features of the endogenous form. This system now offers the possibility to study structure-function relationships and to determine the role of this kinase in growth control.
Mol Biol Cell 1992 Jan
PMID:Functional expression and growth factor activation of an epitope-tagged p44 mitogen-activated protein kinase, p44mapk. 137 23

To understand better the specificity of peptide binding by MHC class I molecules, we have evaluated the capacity of a panel of unrelated peptides to compete for the presentation of viral peptides presented by HLA-A3 and HLA-B27. The HIV-Nef7F peptide (74-82) was presented by HLA-A3 to Nef-specific HLA-A3-restricted CTL lines, and the influenza nucleoprotein peptide NP(380-393) was presented by HLA-B27 to NP(380-393)-specific HLA-B27-restricted CTL lines. In addition, we have extended studies from our group that have evaluated the capacity of a similar panel of peptides to inhibit presentation of an influenza nucleoprotein peptide NP (335-349) by HLA-B37 and a matrix peptide, M1 (57-68), by HLA-A2 to the appropriate peptide-specific CTL lines. Out of 41 peptides tested, only five bound to more than one of the MHC molecules analyzed. Pairwise comparisons of the peptide binding specificities among these four different class I molecules revealed no common competitor peptides in four of the six possible comparisons. Thus, each class I molecule appears to have a functionally distinct peptide binding site, as reflected by the ability to bind largely non-overlapping sets of peptides.
Mol Immunol 1992 Sep
PMID:The peptide binding specificity of HLA class I molecules is largely allele-specific and non-overlapping. 137 81


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