Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cysteine residue in the cytoplasmic domain at position 489 of the sequence of the glycoprotein (G protein) isolated from vesicular-stomatitis virions is completely blocked for carboxymethylation. After release of covalently bound fatty acids by hydroxylamine at pH 6.8, this cysteine residue could be specifically labelled by iodo[14C]acetic acid. Reaction products were analysed after specific cleavage of labelled G protein at asparagine-glycine bonds by hydroxylamine at pH 9.3, which generated a C-terminal peptide of Mr 15,300 containing only the single cysteine residue. Bromelain digestion of [3H]palmitic acid-labelled membrane fractions of vesicular-stomatitis-virus-infected baby-hamster kidney cells removed almost completely the 3H radioactivity from the cytoplasmic domain of the G protein, whereas the ectodomain was completely protected by the microsomal membrane. This result indicates that the acylation site of the G protein is exposed on the cytoplasmic side of intracellular membranes. Taken together, both biochemical techniques strongly suggest that the single cysteine-489 residue, which is located six amino acid residues distal to the putative transmembrane domain, is the acylation site. The thioester bond between palmitic acid and the G protein is quite resistant to hydroxylamine treatment (0.32 M at pH 6.8 for 1 h at 37 degrees C) compared with the reactivity of the thioester linkage in palmitoyl-CoA, which is cleaved at relatively low concentrations of hydroxylamine (0.05 M).
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PMID:Fatty acid acylation at the single cysteine residue in the cytoplasmic domain of the glycoprotein of vesicular-stomatitis virus. 285

An enzymatic activity associated with intracellular membrane fractions of Merwin plasma cell tumor II, baby hamster kidney, and chicken embryo fibroblast cells and bovine kidney has been characterized which covalently links fatty acids onto the G protein of vesicular stomatitis virus. Exogenous G protein extracted from native vesicular stomatitis virus particles can be acylated in vitro only after it has been previously deacylated. The fatty acids transferred in vitro are sensitive to treatment with hydroxylamine, indicating an ester linkage. Cell-free acyl transfer was also observed with endogenous G protein present in membrane fractions prepared from vesicular stomatitis virus-infected cells. In this case, the fatty acids become linked to a G protein species (G1) which is not terminally glycosylated and therefore has not entered the trans-Golgi compartment. The same G protein species also becomes acylated in infected cells during short pulses with radioactive palmitic acid. Acylation of the G protein in vitro with free palmitic or myristic acid is energy-dependent, and the addition of ATP is specifically required. Other nucleoside triphosphates cannot substitute for ATP in the activation of free acyl chains. Alternatively, activated fatty acids linked in a high energy thioester bond to coenzyme A, e.g. [14C] palmitoyl-CoA, are suitable lipid donors in the in vitro acylation reactions. Palmitic acid transfer onto G protein shows the typical characteristics of an enzyme-catalyzed reaction.
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PMID:Cell-free fatty acylation of microsomal integrated and detergent-solubilized glycoprotein of vesicular stomatitis virus. 303 Oct 69

The fatty acids bound to the glycoproteins of Sindbis and vesicular stomatitis viruses can be released by treating the protein with 1 M hydroxylamine at pH 8.0, but the rates of release vary greatly among the three proteins. The most labile fatty acyl bonds were in the Sindbis virus PE2/E2 proteins and the most stable were in the E1 protein. Some of the fatty acids in Sindbis virus glycoproteins were reduced to the alcohol after treatment with sodium borohydride, indicating that protein-bound fatty acids could be in thiolester linkage. Sindbis virus PE2/E2 has several cysteine residues near the carboxy terminus, a region of the protein postulated to be localized on the inside (cytoplasmic face) of the bilayer, and protease digestion of microsomal membranes containing E2 protein removed a small portion of this cytoplasmic tail as well as significant amounts of the fatty acid. For the vesicular stomatitis virus G protein, the sensitivity of fatty acid hydrolysis appeared to depend on the conformation of the protein and a significant fraction of G protein was converted to a disulfide-linked dimer by hydroxylamine. These data implicate cysteinyl groups on these proteins as sites involved in fatty acid acylation.
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PMID:Release of fatty acids from virus glycoproteins by hydroxylamine. 632 73

Influenza virus hemagglutinin (HA) subtype H7 expressed from a baculovirus vector in insect cells requires cysteine residues for palmitoylation. Mutant HA devoid of fatty acids shows hemagglutinating and hemolytic activities almost identical to those of the acylated wild-type HA (wt). Using a membrane mixing assay (R18), neither the kinetics nor the pH dependence of fusion induced by wt or mutant HA was significantly different from virus-induced fusion. HA-induced fusion of insect cells with human erythrocyte ghosts could also be demonstrated by a cytoplasmic content mixing assay. Both species of recombinant HA induced the flow of lucifer yellow from preloaded ghosts into the cytoplasm of HA-bearing cells. This indicates that membrane fusion mediated by wild-type and fatty-acid-free HA includes both leaflets of the lipid bilayers. Hydroxylamine treatment of wt HA (H7) and fatty-acid-free mutant HA present in lysates of insect cells led to the complete inhibition of hemolytic activity. Deacylation of spike proteins by NH2OH treatment of virus particles resulted in a block of hemolytic activity in influenza virus subtypes H7 and H10 as well as of that in the togaviruses Semliki Forest and Sindbis virus. However, the same treatment did not affect subtypes H2 and H3 or two vesicular stomatitis virus serotypes. With such a differential effect whether or not fatty acids are present in the spike proteins of the different virus particles, hydroxylamine must have other effects than just deacylation, and therefore seems unsuitable for the study of the biological functions of acylproteins.
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PMID:Assessment of fusogenic properties of influenza virus hemagglutinin deacylated by site-directed mutagenesis and hydroxylamine treatment. 779 71