Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four different glycopeptides can be distinguished after pronase digestion of influenza A virus glycoproteins: Ia and Ib, containing N-acetylglucosamine, mannose, galactose, and fucose, and IIa and IIb, containing mannose and N-acetylglucosamine. All glycopeptides yielded N-acetylglucosaminyl-asparagine after mild acid hydrolysis. There was no evidence for O-glycosidic bonds. Thus, the carbohydrate complement is linked to the polypeptide exclusively by N-glycosidic linkages between N-acetylglucosamine and asparagine.
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PMID:Carbohydrates of influenza virus. III. Nature of oligosaccharide-protein linkage in viral glycoproteins. 50 97

Chicken fibroblasts and MDCK cells were infected with influenza virus labelled with either 3H-uridine or 14C-amino acids, and the location in infected cells and properties of input virus-labelled structures were studied. Input virus RNA and protein were found in the cytoplasm of nuclei 1 h p.i. A part of the intranuclear parental structures was associated with chromatin while the other part could be extracted from nucleoplasm by 0.16 M-NaCl and represented free ribonucleoprotein (RNP) particles. These RNPs sedimented in glycerol velocity gradients at 40 to 70S, very similar to cytoplasmic RNPs, but differed distinctly from them in buoyant density. The bulk of cytoplasmic RNPs after fixation with formaldehyde banded in CsCl at 1.34 g/ml while nucleoplasmic RNPs banded at 1.39 or 1.41 g/ml. RNPs isolated from virions and infected cells contained the NP polypeptide which was revealed by SDS-PAGE analysis as a double band. The ratio of the two bands varied in cytoplasmic and nucleoplasmic RNPs, the lower band being dominant in cytoplasmic but not in nucleoplasmic RNPs. In addition, cytoplasmic RNPs were phosphorylated. The possible significance of intracellular RNP modifications for virus replication is discussed.
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PMID:Cytoplasmic and nuclear input virus RNPs in influenza virus-infected cells. 54 71

Sigma bromelain (EC 3.4.22.4) was used to isolate the haemagglutinin (HA) from the MRC-11 (H3N2) and A/U.S.S.R./90/77 (H1N1) influenza A virus strains. Sedimentation analysis of bromelain-solubilized preparations revealed 9.5S and 5.5S protein components, the former being identified as the bromelain-released haemagglutinin (BHA). No residual neuraminidase (NA) activity was detected in the BHA isolated from the MRC-11 strain whereas up to 80 per cent of the enzymatically active NA was found to be preserved in the electrophoretically pure BHA isolated from the A/U.S.S.R./90/77 strain. Increased electrophoretic mobilities were exhibited by both the light and heavy chains of the BHA subunit. The difference observed in the molecular weights of the polypeptide fragments removed by bromelain from the light chains is interpreted in terms of the different depth of penetration of antigenically distinct HAs through the influenza virus lipid membrane. Splitting off of approximately 15 and 26 per cent of the sugars from the carbohydrate portions of the light and heavy chains respectively, was demonstrated. This suggested involvement of glycosidase impurities present in the bromelain preparation employed. The rod-shaped BHA molecules proved to be 110 +/- 5 Angstrom long and 40 +/- 5 Angstrom wide as measured by electron microscopy. It is proposed that the 45,000-molecular-weight polypeptide observed constantly in egg-grown influenza viruses is host actin.
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PMID:Structure of bromelain-released influenza virus haemagglutinin as revealed by electrophoresis, sedimentation and electron microscopy. 54 1

Purified and unpurified cell-free systems prepared from the chorioallantoic membrane of embryonated eggs were tested for polypeptide synthesis in the presence and absence of influenza virus RNA. Both systems exhibited an endogenous messenger activity determining 3H-phenylalanine incorporation into polypeptides in the absence of virus RNA. However, addition of influenza virus RNA to the systems clearly stimulated amino acid incorporation into polypeptides, offering the possibility of studying some aspects of the viral protein biosynthesis mechanism.
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PMID:Stimulation by inlfuenza virus RNA of 3H-phenylalanine incorporation in a cell-free system. 56 74

Ortho- and parmyxoviruses were isolated at high frequencies from cloacal and tracheal samples of 334 domestic and 161 migrating ducks in Miyagi and Akita Prefectures, Japan, in the winter of 1976--77. Forty-four hemagglutinating agents were isolated from these ducks. The frequency of virus isolation was much higher from the cloacal samples (6.3%) than the tracheal samples (2.6%). However, no significant difference was found in the isolation ratio between the domestic (7.8%) and migrating (6.8%) ducks. Nine strains of the hemagglutinating agents were identified as influenza A viruses and confirmed to be in pure form by complement-fixation (CF) tests and from their polypeptide profiles. The antigenic characterization of the influenza A viruses revealed the presence of several subtypes; Hav5Nav-2-3, Hav6Neq2, Hav6N2, Hav7Neq2 and Hav7N2.
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PMID:Isolation of orthomyxoviruses from migrating and domestic ducks in northern Japan in 1976--1977. 75 40

The genome RNA species of influenza type C virions were analyzed by polyacrylamide gel electrophoresis. The pattern obtained was found to resemble those of other influenza viruses. Six RNA species were resolved, with estimated sizes ranging from 0.37 X 10(6) to 1.25 X 10(6) daltons. The internal ribonucleoproteins of influenza C virions were found to sediment heterogeneously in glycerol velocity gradients as demonstrated previously with influenza A/WSN virus. The ribonucleoproteins possessed diameters of 12 to 15 nm, with lengths ranging from 30 to 100 nm. Of the three major virion polypeptides (molecular weights, 88,000, 66,000, and 26,000), only the largest is glycosylated. Similar polypeptide species were present in influenza C virions of five different strains. All three major proteins of influenza C virions possess electrophoretic mobilities distinguishable from those of the major polypeptides of influenza A/WSN. The 66,000-dalton protein is associated with the ribonucleoprotein components. Two additional glycosylated polypeptides, with estimated molecular weights of 65,000 and 30,000, were detected in virions grown in embryonated eggs, but not in virus particles obtained from chicken embryo fibroblasts.
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PMID:Structural components of influenza C virions. 83 41

The authors show that a thymus polypeptide extract, TP1, prepared by them has the effedt of stimulating the formation of anti-influenza serum antibodies and do not show antigenic properties. The extract causes increase of serum lymphocytes. Electrophoretic analysis in polyacrylamide gel reveals a number of 11 fraction, while paper chromatography for amino acids, a number of 12 spots.
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PMID:Stimulation of anti-influenza serum antibody formation in the rat using bovine thymus polypeptide extract. 84 69

The carbohydrate moiety of the influenza glycoproteins NA, HA(1), and HA(2) were analyzed by labeling with radioactive sugars. Analysis of glycopeptides obtained after digestion with Pronase indicated that there are at least two different types of carbohydrate side chains. The side chain of type I is composed of glucosamine, mannose, galactose, and fucose. It is found on NA, HA(1), and HA(2). The side chain of type II contains a high amount of mannose and is found only on NA and HA(2). The molecular weights of the corresponding glycopeptides obtained from virus grown in chicken embryo cells are 2,600 for type I and 2,000 for type II. The glycoproteins of virus grown in MDBK cells have a higher molecular weight than those of virus grown in chicken embryo cells, and there is a corresponding difference in the molecular weights of the glycopeptides. Under conditions of partial inhibition of glycosylation, virus particles were isolated that contained hemagglutinin with reduced carbohydrate content. Glycopeptide analysis indicated that this reduction is due to the lack of whole carbohydrate side chains and not to the incorporation of incomplete ones. This observation suggests that glycosylation of the viral glycoproteins involves en bloc transfer of the core sugars to the polypeptide chains.
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PMID:Carbohydrates of influenza virus. I. Glycopeptides derived from viral glycoproteins after labeling with radioactive sugars. 88 48

Neuraminidase was isolated by proteolysis of the X7-(F1) (HON2) strain of influenza virus, and purified by gel filtration. The molecule contained a total of 46% (w/w) carbohydrate. The Mr was estimated as 152 500 (sedimentation diffusion) and 147 000 (sedimentation equilibrium). In 6 M guanidine-HCl the molecular weight was halved to 66 000 (sedimentation equilibrium). After irreversible reduction and blocking of sulphydryl groups the molecular weight was halved again to 33 500 (sedimentation equilibrium). These results confirm the tetrameric model of neuraminidase structure. They also provide strong evidence that the tetramer is composed of two disulphide linked dimers, themselves associated by non-covalent linkages. Theoretical considerations based on this model predict that assembly of the molecule must be accompanied by allosteric conformational changes in the subunits. The high carbohydrate content was thought to explain the discrepancy between the molecular weight values for the neuraminidase polypeptide obtained by different methods, and also the exceptional resistance of the molecule to digestion by proteolytic enzymes.
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PMID:Structural and composition of the N2 neuraminidase of influenza virus. Effect of carbohydrate content on the validity of molecular weight estimations. 91 84

The thymus polypeptide extract TP1 administered to X-rayed animals shows a protecting effect on the level of serum anti-influenza antibodies in the rats inoculated with A2 influenza vaccine and reduces the haemagglutinating titres in the mice inoculated with the A PR8 influenza virus.
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PMID:Influence of a thymus polypeptide extract (TP1) on immunogenesis and on experimental influenza infection in x-rayed animals. 91 26


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