Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.5.1.52 (PNGase F)
1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biochemical properties of the concanavalin A-binding 43-kDa glycoprotein (gp43) of Paracoccidioides brasiliensis and its deglycosylated form were compared. Deglycosylation was achieved by treatment with trifluoromethanesulfonic acid, endoglycosidase H, N-glycanase, or metabolically, by growing cells with tunicamycin. The resulting antigen in all cases had Mr 38,000, and probably derived from the gp43 by loss of N-linked high-mannose oligosaccharide chains. The presence of galactopyranose units in the carbohydrate chains was suggested by antigen binding to peanut lectin. Pulse and chase experiments using [35S]methionine metabolic labeling of P. brasiliensis growing in the presence of tunicamycin showed that the N-linked chains of gp43 are not required for antigen secretion. The 38-kDa antigen was more susceptible than the native antigen to the action of papain and pronase, thus indicating a protective role of the carbohydrate moiety against proteolysis. Both forms are equally resistant to endogenous proteases at neutral pH. The gp43, itself, has a proteolytic activity at pH 5-6, but not at neutral pH. Deglycosylation with endoglycosidase H or tunicamycin preserved epitopes in the 38-kDa molecule reactive with (a) antibodies from patients with paracoccidioidomycosis, or rabbit immunized with the gp43 and (b) mouse monoclonal antibodies against the gp43 antigen. The present results provide a basis for the understanding of diagnostic reactions and fungal virulence involving the gp43 exocellular antigen of P. brasiliensis.
...
PMID:The 43-kDa glycoprotein from the human pathogen Paracoccidioides brasiliensis and its deglycosylated form: excretion and susceptibility to proteolysis. 189 73

The envelope glycoprotein of HIV-I in infected, cultured human T cells is synthesized as a precursor of apparent Mr 160 kDa (gp160) and is cleaved to two glycoproteins, gp120 and gp41, which are the mature envelope glycoproteins in the virus. Neither the temporal and spatial features of glycosylation nor the oligosaccharide processing and proteolytic cleavage of the envelope glycoprotein are well understood. To understand more about these events, we investigated the glycosylation and cleavage of the envelope glycoproteins in the CD4+ human cell line, Molt-3, persistently infected with HIV-I (HTLV IIIB). The carbohydrate analysis of gp160 and gp120 and the behavior of the glycoproteins and glycopeptides derived from them on immobilized lectins demonstrate that both of these glycoproteins contain complex- and high-mannose-type Asn-linked oligosaccharides. In addition, the N-glycanase-resistant oligosaccharides of gp120 were found to contain N-acetyl-galactosamine, a common constituent of Ser/Thr-linked oligosaccharides. Pulse-chase analysis of the conversion of [35S]cysteine-labeled gp160 showed that in Molt-3 cells it takes about 2 h for gp120 to arise with a half-time of conversion of about 5 h. At its earliest detectable occurrence, gp120 was found to contain complex-type Asn-linked oligosaccharides. Taken together, these results indicate that proteolytic cleavage of gp160 to gp120 and gp41 occurs either within the trans-Golgi or in a distal compartment.
...
PMID:gp160 of HIV-I synthesized by persistently infected Molt-3 cells is terminally glycosylated: evidence that cleavage of gp160 occurs subsequent to oligosaccharide processing. 189 96

The oligosaccharide structures linked to Asn289 of a recombinant (r) variant (R561S) human plasminogen (HPg) expressed in Chinese hamster ovary (CHO) cells, after transfection of these cells with a plasmid containing the cDNA coding for the variant HPg, have been determined. Employing high-performance anion-exchange liquid chromatography mapping of the oligosaccharide units cleaved from the protein by glycopeptidase F, compared with elution positions of standard oligosaccharides, coupled with monosaccharide compositional determinations and analyses of sequential exoglycosidase digestions and specific lectin binding, we find that considerable microheterogeneity in oligosaccharide structure exists at this sole potential N-linked glycosylation site on HPg. A variety of high-mannose structures, as well as bi-, tri-, and tetraantennary complex-type carbohydrate, has been found, in relative amounts of 1-25% of the total oligosaccharides. The complex-type structures contain variable amounts of sialic acid (Sia), ranging from 0 to 5 mol/mol of oligosaccharide in the different glycan structures. Neither hybrid-type molecules, N-acetylglucosamine bisecting oligosaccharides, nor N-acetyllactosaminyl-repeat structures were found to be present in the complex-type carbohydrate pool in observable amounts. Of interest, a significant portion of the Sia exists an outer arm structures in an (alpha 2,6) linkage to the penultimate galactose, a novel finding in CHO cell-directed glycosylation.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Oligosaccharide structures present on asparagine-289 of recombinant human plasminogen expressed in a Chinese hamster ovary cell line. 189 31

IgD receptors on murine T cells have been reported in this issue [Tamma, S. M. L., Amin, A. R., Finkelman, F. D., Chen, Y.-W., Thorbecke, G. J. & Coico, R. F. (1991) Proc. Natl. Acad. Sci. USA 88, 9233-9237] to bind either the first or third constant region of the heavy-chain of IgD molecules--findings that could not be satisfactorily explained by IgD amino acid sequences. We now find that boiled IgD molecules or low-Mr fragments from protease-digested IgD still inhibit binding of IgD-coated erythrocytes to IgD receptors. This inhibitory activity can be absorbed with the murine IgD-binding lectin from Griffonia simplicifolia 1 (GS-1) immobilized on Sepharose. N-linked glycans, obtained from N-glycanase-treated IgD and purified by binding to GS-1-Sepharose, also inhibit rosette formation of T-helper cells bearing receptors for IgD with IgD- or mutant IgD-coated erythrocytes. Deglycosylated IgD, produced by treatment with N-glycanase, no longer binds to the lectin and fails to inhibit IgD rosetting. Binding of intact IgD to T cells is also competitively inhibited by N-acetylgalactosamine, galactose, N-acetylglucosamine, and neoglycoproteins containing these sugars. These results clearly show that N-linked glycans, present in both the first and third constant regions of the delta heavy-chain domains, are prerequisites for binding of IgD to IgD receptors.
...
PMID:Specificity of the murine IgD receptor on T cells is for N-linked glycans on IgD molecules. 192 87

The carbohydrate composition and the immunoreactivity of the S and M glycoproteins of the coronavirus TGEV were studied at different stages of their maturation. The biosynthesis of S and M was analyzed in the presence of tunicamycin and monensin. The effect of treatment with endoglycosidases H and F and glycopeptidase F on the precursors and mature forms of S and M were also examined. Species 175K and 29K were characterized as high mannose forms of S and M, respectively, and species 220K and 30-36K as complex type glycosylated forms of these two proteins. M was present mainly as a 29K species in mature virions whereas the 175K form of S was not detected, thus implying that the two proteins undergo Golgi modifications at a far different efficiency. Anti-S and -M monoclonal antibodies were examined for their reactivity towards polypeptide species either treated with endo H or produced in the presence of tunicamycin. It was found that (i) among the four major antigenic sites previously defined (Delmas et al., 1986), only site C (amino acids 363 to 371) was notably expressed by the unglycosylated S polypeptide 155K, whereas the three other sites were dependent upon core-glycosylation, (ii) three of the four anti-M mAbs tested did not recognize the unglycosylated M polypeptide 26K. These data led us to conclude that co-translational, but not terminal glycosylation is an essential requirement for both acquisition and maintenance of the antigenicity of TGEV glycoproteins.
...
PMID:Carbohydrate-induced conformational changes strongly modulate the antigenicity of coronavirus TGEV glycoproteins S and M. 195 Jan 69

After adipocytes were labeled with Na2[35SO4], immunoadsorbed with immobilized antilipoprotein lipase, and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and fluorography, a labeled band was identified at 59,700 daltons, the molecular mass of chicken lipoprotein lipase (LPL). Excess unlabeled LPL prevented the immunoadsorption of this labeled species, hence the labeled species was determined to be LPL. Digestion of LPL with endo-beta-N-acetylglucosaminidase H (Endo H) caused a shift in mobility of LPL in SDS-PAGE with no loss of radioactivity, whereas digestion with glycopeptidase F resulted in removal of 99% of the radioactivity. Adipocytes cultured with Trans35S-label and tunicamycin produced an LPL species of 52,000 daltons, but tunicamycin abolished the incorporation of 35SO4 into LPL. This established that 35SO4 was incorporated into an N-linked oligosaccharide of LPL. Endo H digestion of pulse-chase labeled LPL revealed the presence of two complex and one high mannose-type N-linked oligosaccharides. A single 35SO4-labeled tryptic peptide was isolated by reverse phase chromatography. The amino acid sequence of the peptide established that the 35SO4 oligosaccharide is conjugated at Asn-45. Behavior of the 35SO4-labeled oligosaccharide on concanavalin A-agarose, sequential exoglycosidase digestion, and chemical analysis of the 35SO4 oligosaccharide confirms that this moiety is of the complex type. Sequential exoglycosidase digestion, thin layer chromatography of the released monosaccharides, and the use of glycosylation inhibitors established that the sulfated sugar is a core N-acetylglucosamine (GlcNAc). The data show that chicken LPL contains two complex and one high mannose N-linked oligosaccharides and that 35SO4 is incorporated into LPL on a GlcNAc residue of a complex oligosaccharide located at Asn-45.
...
PMID:Occurrence of sulfate in an asparagine-linked complex oligosaccharide of chicken adipose lipoprotein lipase. 198 32

The beta-subunit of human choriogonadotropin (hCG) has two complex type N-linked and four O-linked carbohydrate chains. To further evaluate the specificity of the carbohydrate moiety on the hCG function, we have expressed hCG beta subunit in the baculovirus insect cell system to modify its carbohydrate structures. The recombinant hCG beta (rhCG beta) was efficiently secreted in the medium and was purified to homogeneity by immunoaffinity chromatography using a highly specific monoclonal antibody against hCG beta. The homogeneity of the recombinant subunit was established by sodium dodecyl sulfate-polyacrylamide gel electrophoresis performed under reducing and nonreducing conditions and reverse phase high performance liquid chromatography. rhCG beta had molecular weights of 22,500 and 33,000 under reducing and nonreducing conditions, respectively. Digestion with N-glycanase cleaved the Mr = 22,500 protein to 18,000, while digestion with Endo H or Endo F yielded an additional protein band of 20,500 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The carbohydrate analysis by pulse amperometry yielded the relative number of 2.5, 2.4, 3.7, and 11.3 residues of fucose, N-acetylgalactosamine, galactose, and mannose, respectively, based on a value of 4 residues for N-acetylglucosamine. Lectin binding studies showed rhCG beta to bind with concanavalin A with a high affinity and not with wheat germ agglutinin. In the studies with endoglycosidases together with the carbohydrate analysis and lectin binding properties, rhCG beta appears to have two high mannose-type N-linked and three to four O-linked carbohydrate simple disaccharide chains. The carbohydrate modification of the beta-subunit did not alter its immunopotency and its ability to combine with hCG alpha. The reconstituted hormone made up of rhCG beta and hCG alpha was found to be similar to hCG in biological properties such as receptor binding and in its ability to stimulate cAMP and steroidogenesis.
...
PMID:Carbohydrate variant of the recombinant beta-subunit of human choriogonadotropin expressed in baculovirus expression system. 199 3

Rubella virus contains two envelope glycoproteins, E1 and E2. The amino acid sequence for both glycoproteins is known, as is the number of N-glycosylation sites. This study has demonstrated the presence of O-linked carbohydrates bound to E2 and determined structural characteristics of the N-linked oligosaccharide chains. O-linked sugars were found to be resistant to digestion with N-glycanase but sensitive to beta-elimination with alkaline borohydride. After treatment with neuraminidase, O-linked sugars bound to peanut agglutinin, suggesting the presence of the disaccharide galactose-N-acetylgalactosamine, masked by sialic acid. The N-linked oligosaccharides were large, probably four-branched, and showed a lectin binding pattern suggesting the complex type, with terminal Gal, GlcNAc and sialic acid. No Endo H-sensitive carbohydrates were detected.
...
PMID:Characterization of carbohydrates linked to rubella virus glycoprotein E2. 201 96

In this study we report that bone and platelet osteonectin are structurally and functionally heterogeneous in terms of glycosylation and collagen binding capacity. The relative sensitivity of bone and platelet osteonectin to specific glycosidases was used to evaluate potential differences in glycosylation. Although native bone and platelet osteonectin are electrophoretically nonidentical, N-glycanase treatment yielded products with the same apparent molecular weight. Bone osteonectin was also susceptible to cleavage by endo H but not to neuraminidase, while platelet osteonectin was susceptible to neuraminidase but not to endo H. In lectin blotting experiments of bone and platelet osteonectin, concanavalin A bound specifically to bone osteonectin but not to platelet osteonectin. However, Lens culinaris agglutinin bound to platelet osteonectin but not to bone osteonectin. These data suggest that bone and platelet osteonectin differ in their oligosaccharide side chain structures, with bone osteonectin possessing a high mannose-type and platelet osteonectin, a complex-type structure. Solid-phase binding techniques were used to functionally evaluate bone and platelet osteonectin in terms of collagen binding. Although bone osteonectin bound specifically to types I, III, and V collagen, platelet osteonectin had no apparent affinity for these collagen types suggesting that the two proteins are also functionally distinct.
...
PMID:The collagen binding specificity of bone and platelet osteonectin is related to differences in glycosylation. 203 56

The dopamine transporter from rat caudate-putamen was photolabeled with [125I]DEEP as previously described. Treatment of photolabeled membranes with neuraminidase and N-glycanase reduced the molecular weight of the [125I]DEEP photolabeled dopamine transporter complex, whereas treatment with alpha-mannosidase had no effect. The solubilized [125I]DEEP photolabeled dopamine transporter complex readily bound to wheat-germ agglutinin but not to concanavalin-A sepharose columns. These results suggest that the carbohydrate moiety of the dopamine transporter is N-linked and contains significant quantities of sialic acid but not high mannose residues. A DEEP binding protein was readily detectable in other brain regions including the nucleus accumbens and olfactory tubercle, but not in the prefrontal cortex, olfactory bulb or hypothalamus under similar conditions. The DEEP binding protein in the other brain regions was similar to that in the striatum.
...
PMID:Dopamine transporter: deglycosylation with exo- and endoglycosidases. 205


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---