Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four vaccines are available in the United Kingdom against influenza virus. All are subunit vaccines, defined as either split-virion or purified surface antigen vaccine; there are two of each distinct type available. Both vaccine types are less reactogenic than whole inactivated virus, with antigenicity induced by viral surface glycoproteins. Here, each of the four vaccines has been characterized by electron microscopy and SDS-PAGE analysis, giving a unique vaccine profile. Three vaccines contain internal viral nucleoprotein which, in the presence of residual haemagglutinin, may induce an influenza A virus cross-reactive cytotoxic T-cell response and thus be of value to vaccine efficacy. Residual lipid was present in three vaccines and recent evidence suggests that pyrogenicity is correlated with the presence of viral lipid with clusters of surface glycoproteins. By a combination of electron microscopic evidence and biochemical characterization, it has been possible to resolve compositional differences, not only between vaccine type, but also between each individual currently available vaccine. Hence, there is the possibility that the morphological differences characterized here may be contributory to potential reactogenic effects subsequent to vaccination.
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PMID:Morphological and biochemical characterization of influenza vaccines commercially available in the United Kingdom. 809 54

Son of sevenless-1 and -2 (Sos-1 and -2) are guanosine nucleotide exchange factors implicated in the activation of Ras by both the insulin and epidermal growth factor signal transduction pathways. Ras appears to function by initiating the activation of cellular protein kinases including mitogen-activated protein (MAP) kinases. Sos proteins contain numerous sequences in their carboxyl-terminal regions which correspond to consensus sites for MAP kinase phosphorylation. To examine whether these sites are substrates for MAP kinases, the cDNA encoding Drosophila Sos (dSos) was tagged with sequences encoding the major antigenic epitope of the influenza virus hemagglutinin (HA) to create a dSosHA fusion construct. dSosHA was transiently expressed in COS-1 cells and immunoprecipitated with anti-HA antibodies. When immune complexes were incubated with purified MAP kinase and [gamma-32P]ATP, a phosphorylated band of 180 kDa was observed when analyzed by SDS-polyacrylamide gel electrophoresis. This band was not present in immunoprecipitations from cells transfected with vector alone. No phosphorylation of the 180 kDa band was seen when immunoprecipitates were incubated with [gamma-32P]ATP in the absence of MAP kinase. Two dimensional analysis of tryptic peptides from dSosHA phosphorylated by MAP kinase in vitro revealed two major phosphorylated species that were also found in dSosHA isolated from COS-1 cells labeled with 32Pi. These results are consistent with the hypothesis that a feedback loop exists wherein growth factor-activated MAP kinases phosphorylate and regulate Sos proteins.
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PMID:Phosphorylation of the Ras nucleotide exchange factor son of sevenless by mitogen-activated protein kinase. 810 39

The oligomeric form of the paramyxovirus simian virus 5 (SV5) fusion (F) glycoprotein has been examined by using chemical cross-linking and sucrose density gradient fractionation. In addition, chemical cross-linking was used to examine the kinetics of assembly of the F oligomer. Analysis by SDS-PAGE on 3.5% gels of the cross-linked F molecules indicated three major species with calculated molecular weights of M(r) approximately 65, M(r) approximately 130, and M(r) approximately 195 kDa, suggesting F monomers, dimers, and trimers, respectively. The cross-linked F species of M(r) approximately 195 kDa migrated on gels faster than influenza virus hemagglutinin trimers and between the dimeric and tetrameric forms of paramyxovirus hemagglutinin-neuraminidase (HN). Furthermore, the F protein oligomer was found to sediment slower than the HN tetramer on sucrose gradient centrifugation. SDS-PAGE analysis of the cross-linked F protein of Newcastle disease virus and human parainfluenza virus 3 showed a pattern very similar to that found for SV5. The data are consistent with those expected for the paramyxovirus F protein being a homotrimer.
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PMID:Studies with cross-linking reagents on the oligomeric form of the paramyxovirus fusion protein. 811 39

We observed previously that cord-like structures which had lengths up to 500 microns or greater were protruding from the surface of HMV-II cells infected with influenza C/Yamagata/1/88 virus (Nishimura et al., 1990, Virology 179, 179-188). Comparison of the cord-forming ability among a number of influenza C isolates revealed that the C/Taylor/1233/47 strain was unique in lacking the ability. It was also found that the major structural proteins, hemagglutinin-esterase (HE), nucleoprotein (NP), and matrix (M), could each be distinguished between C/Yamagata/1/88 and C/Taylor/1233/47 viruses by SDS-polyacrylamide gel electrophoresis. To determine the genes involved in the cord formation, a series of reassortant viruses were prepared between C/Yamagata/1/88 and C/Taylor/1233/47, and parental derivation of genes coding for HE, NP, and M was determined by gel electrophoresis. All reassortants which derived M gene from C/Yamagata/1/88, irrespective of derivation of genes coding for HE and NP, had the ability to generate cords, whereas none of reassortants which derived M gene from C/Taylor/1233/47 were capable of producing cords. With respect to several representative reassortants, the origins of genes encoding the polymerase proteins (PB2, PB1, P3) and the nonstructural proteins (NS1, NS2) were determined by T1-oligonucleotide fingerprinting of the isolated RNA segments. The results suggested that none of genes coding for these proteins are exclusively associated with the cord formation. Thus, it is likely that the M gene is the key determinant of the cord-forming ability of influenza C viruses. Nucleotide sequence analysis of the M genes revealed that compared to C/Yamagata/1/88, C/Taylor/1233/47 had two amino acid substitutions in the M molecule at positions 24 (Ala-->Thr) and 133 (Asp-->Asn).
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PMID:The ability of influenza C virus to generate cord-like structures is influenced by the gene coding for M protein. 812 18

The post-translational processing of the influenza C virus glycoprotein HEF was analysed. In cells infected with influenza C virus, HEF protein is synthesized as a glycosylated 80K polypeptide. A post-translational conformational rearrangement involving the formation of intramolecular disulphide bonds results in a decrease in its electrophoretic mobility. Therefore, SDS-PAGE under non-reducing conditions suggests an Mr of about 100K, whereas under reducing conditions an 80K protein is observed which is in accordance with the sequence data. The 100K form was detected 10 min after synthesis of HEF, and transport to the cell surface took about 60 min. This result indicates that the conformational change presumably occurs in the endoplasmic reticulum. A difference in post-translational processing was observed when the HEF gene was expressed in the absence of other influenza C virus genes. In cells infected with recombinant simian virus 40, the 80K precursor was synthesized, but this protein was neither converted to the 100K form nor transported to the cell surface. Deletion of the short cytoplasmic tail of HEF (Arg-Thr-Lys) or replacement of the two basic amino acids by hydrophobic (Ile) or acidic residues (Glu) resulted in HEF protein which was partially converted to the 100K form. Influenza C virus glycoprotein obtained after transient expression of the HEF gene using the vaccinia virus system was completely converted to the 100K form. However, in neither expression system was HEF transported to the cell surface. The possibility is discussed that the interaction of HEF with another viral protein is required for the post-translational folding and transport of this glycoprotein. The M protein of influenza C virus is suggested as a candidate for the chaperone which might interact with the cytoplasmic tail of HEF.
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PMID:Post-translational folding of the influenza C virus glycoprotein HEF: defective processing in cells expressing the cloned gene. 817 64

The PKC1 gene of the budding yeast Saccharomyces cerevisiae encodes a homolog of the alpha, beta, and gamma isoforms of mammalian protein kinase C (PKC) that is essential for cell growth. Loss of PKC1 function results in a cell lysis defect that is due to a deficiency in cell wall construction. In this study, Pkc1p was modified at its COOH terminus with the influenza virus hemagglutinin epitope and was detected by SDS-polyacrylamide gel electrophoresis as a 145- and 150-kDa doublet when overproduced in yeast cells. Pkc1p displayed intrinsic Ser/Thr protein kinase activity in vitro, possessing a substrate specificity similar to that described for mammalian PKC. Specifically, preferred substrates possess an arginine at position -3 and a basic residue at position +2 relative to the target site. A catalytically inactive missense mutant of Pkc1p failed to complement a pkc1 delta mutant, suggesting that protein kinase activity is required for the biological function of Pkc1p. Both wild-type Pkc1p and the inactive form were isolated as phosphoproteins, indicating that Pkc1p is phosphorylated in vivo by another protein kinase. In vitro protein kinase activity of Pkc1p was not dependent on activating cofactors normally required for stimulation of mammalian PKC. However, mutational incapacitation of the pseudosubstrate site of Pkc1p resulted in constitutive activation of the enzyme, both in vivo and in vitro, suggesting that Pkc1p is normally regulated by a mechanism similar to that of its mammalian counterparts. The apparent molecular mass and substrate specificity of Pkc1p, together with its failure to respond to activating cofactors, suggest that this enzyme is distinct from an enzyme purified previously from budding yeast that has enzymatic properties similar to those of mammalian PKC.
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PMID:Saccharomyces cerevisiae PKC1 encodes a protein kinase C (PKC) homolog with a substrate specificity similar to that of mammalian PKC. 820 5

An immunoblotting procedure was used to determine the specificity and examine some of the properties of antibodies produced following infection of mice with influenza virus or inoculation with noninfectious material with Alhydrogel or complete Freund's adjuvant. The noninfectious material used was beta-propiolactone-inactivated influenza virus and a preparation (HANA) enriched for the surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). When influenza viral proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under nonreducing conditions, each of the anti-viral antisera tested exhibited strong binding. Under reducing conditions, however, much weaker binding was observed especially towards the HA1 subunit of HA. This was particularly apparent with antisera raised to virus or HANA in the absence of adjuvant. A panel of monoclonal antibodies directed to HA also bound well to viral HA separated by SDS-PAGE under nonreducing conditions but failed to recognize epitopes on HA1 separated under reducing conditions. These results suggest that when HA is reduced and immobilized on a solid support, it does not display the conformational features essential for the integrity of all epitopes. The immunoblotting procedure was also used to determine the isotype of anti-viral antibody directed against individual viral proteins and to detect matrix protein 2 (M2) in purified influenza virions and influenza-infected cells using antisera raised to a synthetic peptide representing a sequence within the M2 protein.
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PMID:A study of the advantages and limitations of immunoblotting procedures for the detection of antibodies against influenza virus. 822 3

The influenza C glycoprotein HEF was analyzed for acetylesterase activity after SDS-polyacrylamide gel electrophoresis and transfer to nitrocellulose membranes. Using a histological esterase assay, the glycoprotein was detected as a colored band indicating that it is enzymatically active. The enzyme activity was not affected by low pH, but was abolished after denaturation by SDS as well as after breaking the disulfide bonds by reducing agents. Glycoprotein inactivated by SDS regained its enzyme activity if the ionic detergent was displaced by either bovine serum albumin or a nonionic detergent. The stability of the enzyme combined with the color assay provides a convenient tool to study the acetylesterase activity of the influenza C virus glycoprotein.
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PMID:Surface glycoprotein of influenza C virus: inactivation and restoration of the acetylesterase activity on nitrocellulose. 826 18

A recombinant baculovirus expressing the M2 protein from influenza A/Ann Arbor/6/60 (H2N2) virus (AA60 virus) was constructed. The expressed M2 protein was recognized by a monoclonal antibody specific for the M2 protein and comigrated with the M2 protein from cells infected with AA60 virus on SDS-polyacrylamide gels. Immunofluorescence studies indicated that the expressed M2 protein was present on the surface of Spodoptera frugiperda (Sf9) cells infected with the recombinant baculovirus. Immunoassays using the expressed M2 protein were able to detect antibodies to the M2 protein in serum samples from humans and ferrets infected with influenza A viruses.
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PMID:Antibody response to the M2 protein of influenza A virus expressed in insect cells. 842 45

Conglutinin is a bovine serum protein which was first described as a vertebrate lectin. This protein belongs to the family of C-type lectins. These lectins are composed of four characteristic domains: (1) an N-terminal cysteine-rich domain, (2) a collagen-like domain, (3) a neck domain and (4) a carbohydrate recognition domain (CRD). Recently lectins have been shown to function as immunoglobulin-independent defence molecules due to a complement-mediated mechanism or opsonization. Our previous study showed that bovine conglutinin can inhibit haemagglutination by influenza A viruses and act by directly neutralizing them due to its lectin properties. In order to elucidate the biological role of the collagen-like domain, a recombinant partial conglutinin lacking this collagen-like domain was produced in an Escherichia coli system and its biological activities were examined. A 497 bp sequence, consisting of a short collagen region (two repeats of G-X-Y amino acid sequences), the neck domain, and the CRD of conglutinin cDNA, was amplified by the reverse-transcriptase PCR technique. The cDNA was transferred to a bacterial expression vector system (pRSET-A) and stable transfectants with a high level of conglutinin production were obtained. SDS/PAGE and Western blotting analyses showed a recombinant fusion protein of 27 kDa. Results of a cross-linking study and gel-filtration assay indicated that the recombinant conglutinin can form a trimeric structure and that it has sugar binding activity and specificity similar to that of native conglutinin. The recombinant conglutinin was also found to inhibit haemagglutination caused by influenza A virus as well as to possess less conglutination activity. These results suggest that in order for conglutinin to inhibit haemagglutination caused by the influenza virus, as well as to have sugar binding activity or to form trimers, it does not require the N-terminal and collagenous domains; however, they are essential for full conglutination activity.
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PMID:Recombinant bovine conglutinin, lacking the N-terminal and collagenous domains, has less conglutination activity but is able to inhibit haemagglutination by influenza A virus. 864 31


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