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

The avidin/biotin system was applied as a general mediator in the adsorption/desorption or immobilization of biologically active macromolecules to solid supports. In this context, model biotinylated proteins (lectins and antibodies) were attached to avidin-coupled Sepharose. As examples for affinity chromatography, peanut agglutinin and anti-transferrin antibody were used to isolate asialofetuin and transferrin, respectively. The capacity and product yields were significantly better than those achieved with conventional affinity chromatography on CNBr-activated Sepharose columns containing the same lectin or antibody. Moreover, the columns were characterized by improved stability properties exhibiting remarkably low levels of leakage.
J Mol Recognit 1990 Jun
PMID:Avidin column as a highly efficient and stable alternative for immobilization of ligands for affinity chromatography. 222 60

In cells isolated from guinea-pig or rat ventricular muscle occurrence and distribution of carbohydrate components of the surface coat were monitored using fluorochrome-coupled lectins. Fluorescence of membrane-bound lectins was assayed by an image analysis system. The lectins ConA, WGA, sWGA, LFA and RCA-I showed specific binding to the whole myocyte surface, indicating a homogeneous distribution of alpha-mannosyl, alpha-glycosyl, N-acetylglucosaminyl, N-acetylneuraminate and beta-galactosyl residues. Binding of DBA and SBA, with specific affinity for N-acetylgalactosaminyl residues, to guinea-pig cardiac myocytes was mainly at the cell poles corresponding to intercalated discs in intact tissue. Both lectins failed to interact with rat myocytes. UEA-I, specific for alpha-L-fucose, bound slightly to rat and not to guinea-pig myocytes. Binding of PNA to guinea-pig myocytes was observed only after cleaving off sialic acids from cell surface, suggesting that sialic acids mask galactosyl-beta(1,3)-N-acetylgalactosamine residues. Specificity of lectin-cell interaction was tested by an inhibition assay where free sugars were tested for their capacity to inhibit lectin binding to the myocytes. When comparing different isolation procedures based on different proteolytic enzymes, the myocytes' affinity to any lectin was found to be qualitatively unchanged. Investigation of lectin-decorated myocytes by means of confocal laser scan microscopy showed that lectin binding sites are not confined to the cell surface but are also present in sarcolemmal invaginations, i.e. transverse tubules. This suggests that the tubular system is lined with a carbohydrate layer similar to, and continuous with, that of the peripheral cell surface.
J Mol Cell Cardiol 1990 Jul
PMID:The cell surface of isolated cardiac myocytes--a light microscope study with use of fluorochrome-coupled lectins. 223 45

Monensin, an inhibitor of Golgi function, was used to investigate the role of this cell compartment in the glycosylation of Leishmania donovani promastigote secretory acid phosphatase (EC 3.1.3.2). Monensin-treated cells demonstrated morphological changes in the Golgi complex and secreted enzyme with an altered electrophoretic mobility: two discrete bands of approximately 95 and 110 kDa were found, as compared to the heterodisperse nature of the enzyme from untreated controls. Chemical deglycosylation by mild acid hydrolysis resulted in a similar effect on the electrophoretic mobility of purified extracellular enzyme. Acid phosphatase was also treated with N-glycosidase F (EC 3.5.1.52) to remove N-linked oligosaccharides. The altered lectin-binding properties of the enzyme after these two treatments demonstrated that an unusual type of galactose-containing acid-labile carbohydrate was present in secretory acid phosphatase in addition to the N-linked oligosaccharides. Further, experiments with 32P-labelled enzyme indicated that phosphodiester bonds were the structural component responsible for the sensitivity of this carbohydrate to mild acid hydrolysis. Cumulatively, these results demonstrated that a novel form of Golgi-mediated posttranslational modification had occurred to the secretory acid phosphatase presumably by the addition of an acid-labile phosphoglycan.
Mol Biochem Parasitol 1990 Mar
PMID:Golgi-mediated post-translational processing of secretory acid phosphatase by Leishmania donovani promastigotes. 232 58

We have examined the role of cell surface glycoconjugates during mouse blastocyst maturation, hatching, attachment, and outgrowth by monitoring the influence of six lectins on blastocyst development in vitro. Two lectins, concanavalin A and wheat germ agglutinin were toxic to blastocysts at the concentrations used. Bandierea simplicifolia lectin 1 (BSL-1) induced abnormal growth, developmental arrest at the hatching stage, and some disruption of cell contacts. Culture with Lotus tetragonolobus lectin-1 (LTA-1) also disrupted cell contacts and caused developmental arrest. The remaining lectins, Dolichos biflorus agglutinin (DBA) and Ulex europaeus agglutinin (UEA), retarded blastocyst hatching and outgrowth but did not induce any major defects, although differentiation of the inner cell mass was limited by both. This study demonstrates that very low concentrations of lectins can disrupt blastocyst development, suggesting that exposed surface saccharide moieties may be involved in interactions between blastomeres and their environment.
Mol Reprod Dev 1990 May
PMID:Lectin-induced abnormalities of mouse blastocyst hatching and outgrowth in vitro. 234 43

In the marine shrimp Sicyonia ingentis, ova lack cortical vesicles at spawning. Previous ultrastructural studies suggested that two different populations of cortical vesicles (dense vesicles and the ring vesicles) appear within 30 min post-spawning. These vesicles undergo sequential exocytosis (exocytosis of the dense vesicles followed by exocytosis of the ring vesicles) that leads to the formation of a hatching envelope around the ovum (see Pillai and Clark: Tissue & Cell 20:941-52, 1988). In the present study, lectins were used as molecular probes to study the development of cortical vesicles subsequent to spawning and the role of these vesicles in formation and elaboration of the hatching envelope. Isolated envelopes were screened with 11 different lectins to determine what group(s) were specific to the envelope glycoconjugates; Concanavalin A (Con A), Griffonia simplicifolia (GS II), Lens culinaris (LCA), and wheat germ agglutinin (WGA) bound to the envelopes. FITC-lectin studies of sectioned ova (fixed at various time points after spawning) utilizing WGA and LCA showed different labelling patterns. Data obtained at the light microscopical level indicated that WGA was specific to the dense vesicles and the outer portion of the envelope, while LCA exhibited specificity for the ring vesicles and the inner portion of the envelope. At the ultrastructural level, gold-LCA labelling was seen associated with the cisternal elements (containing ring-shaped structures), ring vesicles, and the inner layer of the fully formed envelope. These data demonstrated that 1) the ring vesicles are formed by fusion of cisternal elements containing ring-shaped structures; 2) the two species of cortical vesicles are chemically heterogeneous; and 3) the components of each type of vesicle contribute to different integral parts (the outer and inner layers) of the hatching envelope.
Mol Reprod Dev 1990 May
PMID:Development of cortical vesicles in Sicyonia ingentis ova: their heterogeneity and role in elaboration of the hatching envelope. 234 49

In attempts to isolate new CHO glycosylation mutants, selection protocols using plant lectins that bind galactose residues of cell surface carbohydrates were applied to mutagenized CHO populations. The lectins were used alone or in combination to obtain seven ricin-resistant phenotypes. Each mutant had distinctive properties compared with previously described ricin-resistant CHO cells. One of the new phenotypes was dominant in somatic cell hybrids, and the others were recessive. Complementation analyses between related lectin-resistant (LecR) phenotypes indicated that each new isolate represented a novel genotype. Five of the mutants had properties typical of new CHO glycosylation mutants. The remaining two mutants were not readily categorized. Although they did not appear to be ricin-internalization or protein-synthesis mutants, they also did not display the marked alterations in sensitivity to several lectins of different sugar specificity expected for glycosylation mutants. The seven new LecR mutants described in these studies brings the total number of different LecR CHO mutants isolated by this and other laboratories to about 40. Criteria for identifying new LecR mutations in CHO cells are discussed.
Somat Cell Mol Genet 1990 May
PMID:Lectin-resistant CHO cells: selection of seven new mutants resistant to ricin. 236 93

Two major isoforms of juvenile hormone esterase (JH esterase) from metamorphosing larvae of Trichoplusia ni were characterized with respect to isoform variation, glycosylation (lectin reactivity) and hormonal induction. Both forms are similarly inducible by juvenile hormone, and both become similarly glycosylated, as measured by concanavalin A binding. In prepupae, synthesis of new JH esterase from a low baseline and glycosylation within fat body are limiting steps in modulation of the level of JH esterase in the hemolymph. In contrast, during the pupal stage regulation of hemolymph JH esterase activity changes to a level other than synthesis of new enzyme or its glycosylation.
Mol Cell Endocrinol 1990 May 07
PMID:Glycosylation and isoform variation of juvenile hormone esterase in the fat body and hemolymph during metamorphosis of Trichoplusia ni (Lepidoptera). 236 69

Hamsters exposed to an intratracheal instillation of human neutrophil elastase (HNE) accumulate an abnormally high number of secretory granules in bronchial but not tracheal epithelial cells. We employed lectin cytochemistry to investigate possible differences in the epithelial cell surface glycoconjugate layer in trachea compared to bronchus which might explain the regional dissimilarity in response to HNE. Portions of glutaraldehyde-fixed trachea and bronchi were incubated in one of several ferritin-labeled lectins prior to embedding for transmission electron microscopy. Lectins from Ricinus communis, Helix pomatia, and Triticum vulgaris bound to the surface of tracheal secretory cells in moderate to profuse amounts, while most bronchial secretory cells showed little or no label with these lectins. Gold-labeled Helix pomatia agglutinin (HPA), a lectin specific for secretory cells, showed a decrease in surface binding to all tracheal secretory cell types within 2 h of HNE instillation, compared to saline controls. In contrast, the majority of bronchial secretory cells showed an HNE-induced increase in surface label from extremely low levels in saline controls. The low levels of lectin binding to bronchial cells, in contrast to the trachea, may indicate the lack of a protective surface glycoconjugate coat, thus explaining the vulnerability of these cells to HNE. The rise in number of accessible HPA binding sites on the surface of bronchial secretory cells exposed to HNE may represent an important event in the pathologic accumulation of secretory granules by these cells.
Am J Respir Cell Mol Biol 1990 Jul
PMID:Lectin cytochemistry reveals differences between hamster trachea and bronchus in the composition of epithelial surface glycoconjugates and in the response of secretory cells to neutrophil elastase. 236 36

Orthorhombic crystals of isolectin I (LOLI) from the seeds of Lathyrus ochrus were first obtained during the STS 29 space shuttle mission. Subsequently, isostructural crystals were also obtained in the laboratory. They belong to the space group P2(1)2(1)2, with cell dimensions a = 135.84 A, b = 63.12 A and c = 54.54 A with one functional entity, a dimer, in the asymmetric unit (Vm = 2.2 A3/Da). The three-dimensional structure of LOLI, which was solved by the molecular replacement method using a 3 A resolution model of pea lectin, has subsequently been refined by using crystallographic data between 8.0 A and 1.9 A resolution, coupled to molecular dynamics and energy minimization techniques. The conventional R-factor is 0.185 for Fo greater than 1 sigma(Fo). The final model includes 220 well-defined water molecules and has root-mean-square deviations from ideal bond distances and angles of 0.004 A and 3 degrees, respectively. Only slight conformation differences have been found between the two alpha beta monomers. The molecular structure of LOLI, the first to be determined from the genus Lathyrus, is very similar to those of concanavalin A, pea lectin and favin. Differences are confined to the loop regions and beta-chain termini. Comparison of equivalent C alpha atom positions between our final model and the pea lectin structure shows slight differences in the association of the two monomers, which are probably due to the different environments in the crystals. The root-mean-square deviation between C alpha atoms of LOLI and pea lectin is 0.40 A. The metal binding sites are very similar in pea lectin, concanavalin A and LOLI. The sugar-binding sites of LOLI are occupied by four well-ordered water molecules each. The cleavage site for one of the monomers is specially well defined in the final electron density map: the amino group of Glul (alpha) seems to form a salt bridge with the carboxylate group of the terminal Asn181 (beta). A detailed analysis of the difference in crystal packing contacts between pea lectin and LOLI shows that, as might be expected, several of the intermolecular interactions are mediated by residues that correspond to substitutions in the LOLI amino acid sequence.
J Mol Biol 1990 Jul 20
PMID:X-ray crystal structure determination and refinement at 1.9 A resolution of isolectin I from the seeds of Lathyrus ochrus. 238 Sep 88

The methionine rich 2S albumin seed storage protein of Bertholletia excelsa has been expressed in seeds of Brassica napus (rapeseed). A chimeric gene driven by the soybean lectin 5' flanking regions was used to produce a fusion protein consisting of the soybean lectin signal peptide and the propeptide of the Brazil nut 2S albumin. Several transgenic plants were studied at the RNA and protein levels; in each case the chimeric gene was expressed and the protein detected at levels ranging from 0.02% to 0.06% of total protein. Transcriptional studies in a particular transgenic plant show that expression of the gene is tissue specific and developmentally regulated during seed maturation. The endogenous napin genes and the introduced gene are regulated differently, with expression of the chimeric gene paralleling that seen when the soybean lectin gene is expressed in other plant species. Western analysis using antibodies to Brazil nut 2S albumins resulted in the detection of a protein whose size is consistent with correct processing of the precursor.
Mol Gen Genet 1990 May
PMID:Expression of the 2S albumin from Bertholletia excelsa in Brassica napus. 238 15


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