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1.
A lectin from the mycelial extract of an endophytic strain of Fusarium solani was purified. Its hemagglutinating activity was inhibited by glycoproteins possessing N-linked as well as O-linked glycans. The thermodynamics and kinetics of binding of glycans and glycoproteins to F. solani lectin was studied using surface plasmon resonance. The lectin showed high affinity for asialofetuin, asialomucin, asialofibrinogen, and thyroglobulin; and comparatively low affinity for mucin, fetuin, fibrinogen, and holotransferrin. Glycoproteins showed several fold higher affinity than their corresponding glycans with significant contribution from enthalpy and positive entropy, suggesting the involvement of non-polar protein-protein interaction. Moreover, the higher affinity of the glycoproteins was due to their faster association rates and low activation energy.  相似文献   

2.
3.
In our previous publication we had reported the purification and characterization of Clitoria ternatea agglutinin from its seeds on fetuin CL agarose affinity column, designated CTA [A. Naeem, S. Haque, R.H. Khan. Protein J., 2007]. Since CTA binds beta-d-galactosides, this lectin can be used as valuable tool for glycobiology studies in biomedical and cancer research. So an attempt was made for a high yielding alternative purification method employing the use of asialofetuin CL agarose column for the above-mentioned lectin, designated CTL. The fetuin affinity purified agglutinin was found similar to asialofetuin affinity purified lectin in SDS pattern, HPLC and N-terminal sequence. The content of lectin was found to be 30mg/30g dry weight of pulse. The yield was 2.8% as compared to 0.3% obtained on fetuin column. The number of tryptophan and tyrosine estimated was four and six per subunit.  相似文献   

4.
Plant lectins are gaining interest because of their interesting biological properties. Several Adenia species, that are being used in traditional medicine to treat many health ailments have shown presence of lectins or carbohydrate binding proteins. Here, we report the purification, characterization and biological significance of N-Acetyl galactosamine specific lectin from Adenia hondala (AHL) from Passifloraceae family. AHL was purified in a single step by affinity chromatography on asialofetuin Sepharose 4B column, characterized and its fine sugar specificity determined by glycan array analysis. AHL is human blood group non specific and also agglutinates rabbit erythrocytes. AHL is a glycoprotein with 12.5% of the carbohydrate, SDS-PAGE, MALDI-TOF-MS and ESI-MS analysis showed that AHL is a monomer of 31.6 kDa. AHL is devoid of DNase activity unlike other Ribosome inactivating proteins (RIPs). Glycan array analysis of AHL revealed its highest affinity for terminal lactosamine or polylactosamine of N- glycans, known to be over expressed in hepatocellular carcinoma and colon cancer. AHL showed strong binding to human hepatocellular carcinoma HepG2 cells with MFI of 59.1 expressing these glycans which was effectively blocked by 93.1% by asialofetuin. AHL showed dose and time dependent growth inhibitory effects on HepG2 cells with IC50 of 4.8 μg/ml. AHL can be explored for its clinical potential.  相似文献   

5.
Purification and saccharide-binding characteristics of a rice lectin   总被引:1,自引:0,他引:1  
A lectin was purified from rice flour by aqueous extraction followed by precipitation by ammonium sulfate and affinity chromatography on p-aminobenzyl 2-acetamido-2-deoxy-1-thio-beta-D-glucoside-succinyl-aminohexylaminyl -Sepharose 4B. The molecular weight of the lectin is approximately 36,000, as determined by sedimentation-equilibrium analysis. It is a tetramer consisting of two different subunits (Mr = 12,000 +/- 1,000 and 9,000 +/- 1,000). Amino acid analysis indicated that the lectin contains very high proportions of half-cystine, glycine, and glutamic acid. All of the half-cystines are present as -S-S- bridges. The lectin agglutinates human A, B, AB, and O erythrocytes, rabbit erythrocytes, human leukocytes, and is mitogenic to human lymphocytes. The hemagglutinating activity of rice lectin is inhibited by 2-acetamido-2-deoxy-D-glucose, methyl 2-acetamido-2-deoxy-beta-D-glucoside, chitobiose, and chitotriose. N-Acetylneuraminic acid was a noninhibitor, but N-acetylneuramin-(2----3)-lactose showed weak inhibition. The agglutinating activity was also inhibited by various sialoglycoproteins. The immobilized rice-lectin bound glycophorin, alpha 1-acid glycoprotein, and fetuin. Asialoglycophorin, asialofetuin, ovomucoid, and human chorionic gonadotropin were bound only partially to the column.  相似文献   

6.
A novel lectin having specificity towards a complex glycoprotein asialofetuin was purified from tubers of Arisaema flavum (Schott.) by affinity chromatography on asialofetuin-linked amino-activated silica beads. A. flavum gave a single peak on HPLC size exclusion and a single band on non-denatured PAGE at pH 4.5. The molecular mass of the lectin, as determined by gel filtration chromatography, was 56 kDa. In SDS-PAGE, pH 8.3, the lectin migrated as a single band of 13.5 kDa, under reducing and non-reducing conditions, indicating the homotetrameric nature. A. flavum lectin (AFL) readily agglutinated rabbit, rat, sheep, goat, and guinea pig erythrocytes but not human ABO blood group erythrocytes even after neuraminidase treatment. This lectin is stable up to 55 degrees C and does not require metal ions for its hemagglutination activity. AFL was completely devoid of sulphur containing amino acids and was rich in aspartic acid and glycine. In Oucterlony's double immunodiffusion, the antisera raised against A. flavum lectin showed distinct lines of identity with those of other araceous lectins. AFL showed potent mitogenic activity towards BALB/c splenocytes and human lymphocytes in comparison to Con A, a well-known plant mitogen. AFL also showed significant in vitro antiproliferative activity towards J774 and P388D1 murine cancer cell lines.  相似文献   

7.
A lectin from the seeds of Amaranthus viridis Linn has been purified by affinity chromatography on asialofetuin-linked amino activated silica. Amaranthus viridis lectin (AVL) has a native molecular mass of 67 kDa. It is a homodimer composed of two 36.6 kDa subunits. The lectin gave a single band in non-denaturing PAGE at pH 4.5 and pH 8.3 and a single peak on HPLC size exclusion and cation exchange columns. The purified lectin was specific for both T-antigen and N-acetyl-D-lactosamine, markers for various carcinomas, in addition to N-acetyl-D-galactosamine, asialofetuin and fetuin. This lectin reacted strongly with red blood cells (RBCs) from human ABO blood groups and rat. It also reacted with rabbit, sheep, goat and guinea pig RBCs. The lectin is a glycoprotein having no metal ion requirement for its activity. Denaturing agents such as urea, thiourea and guanidine-HCl had no effect on its activity when treated for 15 minutes. AVL showed significant antiproliferative activity towards HB98 and P388D1 murine cancer cell lines. It also exerted antifungal activity against phytopathogenic fungi Botrytis cincerea and Fusarium oxysporum but not against Rhizoctonia solani, Trichoderma reesei, Alternaria solani and Fusarium graminearum.  相似文献   

8.
A new N-acetyl-D-glucosamine (GlcNAc) specific lectin was identified and purified from the fruiting body of the Australian indigenous mushroom Psathyrella asperospora. The functional lectin, named PAL, showed hemagglutination activity against neuraminidase treated rabbit and human blood types A, B and O, and exhibited high binding specificity towards GlcNAc, as well as mucin and fetuin, but not against asialofetuin. PAL purified to homogeneity by a combination of ammonium sulfate precipitation, chitin affinity chromatography and size exclusion chromatography, was monomeric with a molecular mass of 41.8 kDa, was stable at temperatures up to 55 °C and between pH 6–10, and did not require divalent cations for optimal activity. De novo sequencing of PAL using LC-MS/MS, identified 10 tryptic peptides that revealed substantial sequence similarity to the GlcNAc recognizing lectins from Psathyrella velutina (PVL) and Agrocybe aegerita (AAL-II) in both the carbohydrate binding and calcium binding sites. Significantly, PAL was also found to exert a potent anti-proliferative effect on HT29 cells (IC50 0.48 μM) that was approximately 3-fold greater than that observed on VERO cells; a difference found to be due to the differential expression of cell surface GlcNAc on HT29 and VERO cells. Further characterization of this activity using propidium iodine staining revealed that PAL induced cell cycle arrest at G2/M phase in a manner dependent on its ability to bind GlcNAc.  相似文献   

9.
A new lectin with the potent mitogenic and in vitro anti-proliferative activity was isolated from the tubers of a wild monocotyledonous plant Sauromatum venosum (Schott), from the family Araceae, by affinity chromatography on the asialofetuin linked amino-activated silica beads. The apparent native molecular mass of S. venosum lectin (SVL), as determined by gel filtration chromatography, was 54 kDa. In HPLC, size exclusion and cation exchange chromatography, SVL gave a single peak and also a single band of 13.5 kDa in SDS-PAGE, pH 8.3, under reducing and non-reducing conditions, indicating that the lectin is composed of four identical subunits. S. venosum lectin agglutinated rabbit, rat, sheep and guinea pig erythrocytes but reacted with goat erythrocytes after the neuraminidase treatment. However, SVL was unable to agglutinate human ABO blood group erythrocytes even after treatment with neuraminidase. SVL was inhibited by N-acetyl-D-Lactosamine (LacNAc), which is an important marker in various carcinomas and a complex desialylated glycoprotein, asialofetuin. The amino acid composition showed that lectin contained a high amount of aspartic acid and glycine but totally devoid of cysteine. However, trace amounts of methionine was present. The lectin showed a potent mitogenic response towards BALB/c splenocytes and human lymphocytes. As the mitogenic stimulation was more than that of Con A, a standard well-known plant mitogen and the response of this lectin was almost double than that of Con A. This lectin is endowed with proliferation of T cells as revealed by IL-2 bioassay but showed no production of immunoglobulins thus indicating the non-stimulation of B cells. SVL significantly inhibited the proliferation of murine cancer cell-lines, i.e., WEHI-279 to 84.6%, J774 to 81%, P388D1 to 74% and A-20 to 47%. In addition, the in vitro anti-proliferative activity of SVL was also evaluated against nine human cancer cell lines representing different organs and tissues namely, T-47D (breast), SiHa (cervix), SK-N-MC (CNS), SK-N-SH (CNS), SW-620 (colon), HT-29 (colon), HEP-2 (liver), OVCAR-5 (ovary) and PC-3 (prostate). SVL showed a significant inhibition towards the entire cell lines except the cell lines from CNS, which showed partial response in comparison to a standard anticancer drug adriamycin which was used at a concentration of 5 x 10(-5) M. Thus the anti-proliferative ability of SVL may be helpful in identification of new lectin probes that can lead to better understanding in the detection and study of certain types of cancer.  相似文献   

10.
An N-acetyl-D-galactosamine (GalNAc)-specific lectin was purified from the edible mushroom, Schizophyllum commune, using affinity chromatography on a porcine stomach mucin (PSM)-Sepharose 4B column. Under reducing and non-reducing conditions, SDS-polyacrylamide gel electrophoresis gave a major band of 31.5 kDa. The Schizophyllum commune lectin (SCL) showed high affinity toward rat erythrocytes and the sugar inhibition assay exhibited its sugar specificity highly toward lactose and N-acetyl-D-galactosamine. It was stable at 55 degrees C for 30 min and at pH 3-10 for 18-h test. The lectin was shown to be a glycoprotein with cytotoxic activity against human epidermoid carcinoma cells. The N-terminus of SCL was blocked but amino acid sequences of internal tryptic peptides showed moderately sequence similarities with some other fungal and plant lectins. Crystals of SCL were obtained by the sitting drop vapour-diffusion method using polyethylene glycol 8000 as the precipitant, and gave an X-ray diffraction pattern to approximately 3.8 angstroms resolution.  相似文献   

11.
Mucin-specific lectin from Sambucus sieboldiana (SSA-M) reacts in Western blotting and ELISA with mucins from porcine stomach, bovine and ovine submaxillary glands, the human milk fat globule membrane, in vitro human ovarian, breast and colonic tumor cell lines, and mucins produced in vivo in the ascites of patients with endometrial and ovarian tumors, but not with fetal bovine fetuin or human transferrin. Sialidase treatment of these mucins led to an increase in the binding of SSA-M, suggesting that sialic acid is not part of the binding site for this lectin. Furthermore, sialic acid did not inhibit lectin binding. Treatment of asialomucin with O-glycanase decreased the binding of SSA-M, confirming the reactivity of the lectin with an O-linked carbohydrate. Treatment of mucins with trifluoromethanesulfonic acid, which removes all but core carbohydrate, led to an increase in the binding of SSA-M, suggesting that the lectin reacts with O-linked core glycans. Indeed, the increased reactivity after sialidase treatment of ovine submaxillary mucin suggests the lectin reacts with peptide-linked N-acetylgalactosamine (GalNAc), since more than 98% of the glycan chains attached to this mucin are sialylated GalNAc. The binding of SSA-M to sialidase-treated porcine mucin was inhibited strongly by GalNAc and disaccharides containing galactose (lactose, melibiose, and N-acetyllactosamine) but not by free galactose (Gal), suggesting that the glycan for optimum binding is Gal beta(1-3)GalNAc. This pattern of inhibition was different to other core glycan-reactive lectins tested, indicating that SSA-M is distinct, and should be of use in the isolation and characterisation of mucins and O-linked glycans.  相似文献   

12.
We earlier reported the mitogenic and immunostimulatory activities of Rhizoctonia bataticola lectin (RBL), purified from phytopathogenic fungus R. bataticola in human PBMC. The lectin demonstrates specificity towards glycoproteins containing complex N-glycans. Since CD45-protein tyrosine phosphatase that abundantly expresses N-glycans is important in T-cell signaling, the study aimed to investigate the involvement of CD45 in the immunomodulatory activities of RBL. Flowcytometry and confocal microscopy studies revealed that RBL exhibited binding to PBMC and colocalized with CD45. The binding was comparable in cells expressing different CD45 isoforms-RA, -RB and -RO. CD45 blocking antibody reduced the binding and proliferation of PBMC induced by RBL. CD45-PTPase inhibitor dephostatin inhibited RBL-induced proliferation, expression of CD25 and pZAP-70. RBL-induced secretion of Th1/Th2 cytokines were significantly inhibited in presence of dephostatin. Also, dephostatin blocked phosphorylation of p38MAPK and STAT-5 that was crucial for the biological functions of RBL. The study demonstrates the involvement of CD45-mediated signaling in RBL-induced PBMC proliferation and Th1/Th2 cytokine secretion through activation of p38MAPK and STAT-5.  相似文献   

13.
A lectin purified from the Tora-bean (Phaseolus vulgaris) by affinity chromatography with Con-A Sepharose was shown to be a glycoprotein containing 7.8% neutral sugars (D-mannose, N-acetyl-D-glucosamine, L-fucose, and D-xylose, in a molar ratio of 9.6 : 2.0 : 0.6 : 0.7). Its molecular weight was 130,000, as estimated by exclusion gel chromatography, and SDS gel electrophoresis showed that it consists of four subunits of molecular weight 32,000. The lectin reacts with various glycoproteins, i.e., blood group substances, human parotid salivary glycoprotein, fetuin, and bovine submaxillary mucin. Divalent cations, such as Ca2+, Mn2+, and Mg2+, appear to stimulate its reactivity. Inhibition tests using the glycopeptide fragment from fetuin and some oligosaccharides, as well as the binding test with 14C-N-acetyl-lactosamine suggest that the sequence of D-galactose, N-acetyl-D-glucosamine, and D-mannose residues in the carbohydrate chain of fetuin is essential for binding.  相似文献   

14.
A lectin with antiproliferative activity towards human cancer cell lines and mitogenic towards human peripheral blood mononuclear cells was purified from the rhizomes of Arundo donax (Linn.) by affinity chromatography on N-acetyl-d-glucosamine linked to epoxy-activated sepharose-6B. The pure preparation apparently yielded a single band of approximately 15 kDa on SDS-PAGE, pH 8.3, under both reducing and non-reducing conditions. The molecular mass of native lectin was 32 kDa as determined by gel filtration chromatography. This showed the lectin to be a dimer, with subunits not held together by disulphide linkages. The A. donax lectin (ADL) agglutinated rabbit erythrocytes and the agglutination was inhibited by N-acetyl-d-glucosamine and its di- and trimer. The lectin was thermostable upto 55 degrees C and showed optimum activity in the range of pH 7.0-9.0 and comprised of 2.1% carbohydrate content.  相似文献   

15.
Vega N  Pérez G 《Phytochemistry》2006,67(4):347-355
A lectin was isolated and characterised from Salvia bogotensis seeds. Removal of the abundant pigments and polysaccharides, which are present in seeds, was an essential step in its purification. Several procedures were assayed and the best suited, including Pectinex treatment, DEAE-cellulose and affinity chromatography, led to a protein being obtained amounting to 18-20mg/100g seeds having high specific agglutination activity (SAA). The lectin specifically agglutinated human Tn erythrocytes and was inhibited by 37mM GalNAc, 0.019mM ovine submaxillary mucin (OSM) or 0.008mM asialo bovine submaxillary mucin (aBSM). Enzyme-linked lectinosorbent assay (ELLSA) revealed strong binding to aOSM and aBSM, corroborating Tn specificity, whereas no binding to fetuin or asialo fetuin was observed. The lectin's monomer MW (38,702Da), amino acid composition, pI, carbohydrate content, deglycosylated form MW, thermal stability and Ca(2+) and Mn(2+) requirements were determined. Evidence of the existence of two glycoforms was obtained. The lectin's specificity and high affinity for the Tn antigen, commonly found in tumour cells, makes this protein a useful tool for immunohistochemical and cellular studies.  相似文献   

16.
Lectins are carbohydrate binding proteins that are gaining attention as important tools for the identification of specific glycan markers expressed during different stages of the cancer. We earlier reported the purification of a mitogenic lectin from human pathogenic fungus Cephalosporium curvulum (CSL) that has complex sugar specificity when analysed by hapten inhibition assay. In the present study, we report the fine sugar specificity of CSL as determined by glycan array analysis. The results revealed that CSL has exquisite specificity towards core fucosylated N-glycans. Fucosylated trimannosyl core is the basic structure required for the binding of CSL. The presence of fucose in the side chain further enhances the avidity of CSL towards such glycans. The affinity of CSL is drastically reduced towards the non-core fucosylated glycans, in spite of their side chain fucosylation. CSL showed no binding to the tested O-glycans and monosaccharides. These observations suggest the unique specificity of CSL towards core fucosylated N-glycans, which was further validated by binding of CSL to human colon cancer epithelial and hepatocarcinoma cell lines namely HT29 and HepG2, respectively, that are known to express core fucosylated N-glycans, using AOL and LCA as positive controls. LCA and AOL are fucose specific lectins that are currently being used clinically for the diagnosis of hepatocellular carcinomas. Most of the gastrointestinal markers express core fucosylated N-glycans. The high affinity and exclusive specificity of CSL towards α1-6 linkage of core fucosylated glycans compared to other fucose specific lectins, makes it a promising molecule that needs to be further explored for its application in the diagnosis of gastrointestinal cancer.  相似文献   

17.
The lectin jacalin immobilized on agarose was found to bind a variety of glycoproteins known to contain typical O-linked oligosaccharides, including human IgA, C1 inhibitor, chorionic gonadotropin, plasminogen, bovine protein Z, bovine coagulation factor X, and fetuin. These proteins were eluted from columns of jacalin-agarose specifically by alpha-galactopyranosides such as melibiose and alpha-methylgalactopyranoside but not by lactose or other sugars. Treatment of asialofetuin with endo--alpha--N--acetylgalactosaminidase eliminated its affinity for the lectin column, and other proteins known to contain only N-linked oligosaccharides such as ovalbumin, transferrin, and alpha 1-acid glycoprotein were not retained by the lectin. Binding of proteins with O-linked oligosaccharides to the lectin column did not require divalent cations and was affected little by changes in pH and ionic strength over a wide range. Virtually all of the glycosidically linked oligosaccharides of fetuin, chorionic gonadotropin, and plasminogen are known to be sialated. Thus, binding of these glycoproteins to jacalin, which is known to have affinity for the core disaccharide, 1-beta-galactopyranosyl-3-(alpha-2-acetamido-2-deoxygalactopyranoside ), in O-linked oligosaccharides of these proteins, was not prevented by the presence of sialic acids. Affinity of oligosaccharides for jacalin did appear to be reduced by occurrence of sialic acids as it was found that higher concentrations of melibiose were required to elute asialofetuin than fetuin from jacalin-agarose. Results of the present study indicate that affinity chromatography using this lectin is a widely applicable technique for identifying and purifying proteins bearing O-linked oligosaccharides.  相似文献   

18.
The lectin of Erythrina corallodendron (Caesalpiniaceae) seeds was purified by heating, ammonium sulfate fractionation, and affinity chromatography on acid-treated Sepharose. The purified lectin is similar to the soybean lectin in being a glycoprotein of molecular weight around 110 000 - 120 000 and having D-galactosephilic activity. This lectin, like the soybean and Pseudomonas aeruginosa lectins, binds to D-galactosamine, N-acetyl-D-galactosamine, alpha- and beta-galactosides as well as to D-galactose. Like these lectins it absorbs onto either untreated or enzyme (papain or neuraminidase) treated human red blood cells, but exhibits a considerable mitogenic activity towards human lymphocytes (predominantly T cells) only after their treatment with neuraminidase. This mitogenic stimulation of lymphocytes is inhibited by D-galactose and its derivatives. Despite the great similarity between them, the E. corallodendron, soybean, and Pseudomonas lectins differ in regard to the intensity of their agglutinating activity towards erythrocytes obtained from different animals and human donors of diverse ABO blood groups. This phenomenon may be attributed to the difference in the affinities of the three lectins to the various D-galactose derivatives and to their molecular properties.  相似文献   

19.
Lectins are non-immune carbohydrate-binding proteins or glycoproteins with specific binding sites for certain glycoconjugates. Fungal lectins have been documented for their antitumour, antiproliferative, immunomodulatory, hypotensive and insecticidal effects. In the present study, a mycelial lectin having molecular mass 55 kDa has been purified and characterized from Lentinus squarrosulus. Biological action spectrum of the lectin revealed agglutination of all human blood types (A, B, O, AB), goat, sheep, rabbit and pig erythrocytes. Neuraminidase treatment of blood type O erythrocytes considerably augmented hemagglutination titre. Carbohydrate inhibition studies showed its high affinity to mucin and asialofetuin. Lectin was purified by a combination of ammonium sulphate precipitation, dialysis, ion exchange chromatography and gel filtration chromatography. Optimum pH for lectin activity was observed to be 6.5–8.0 and optimum temperature was 25–30°C. Lectin showed poor pH stability and was stable within pH 7.0–7.5. It was highly thermostable and could withstand temperature upto 70°C. Lectin activity was sensitive to ethylenediaminetetraacetic acid and denaturants.  相似文献   

20.
A new procedure for isolating a L-fucose-specific lectin from the mushroom Aleuria aurantia is described. The fine specificity of the purified lectin was determined by inhibition of agglutination of human red blood cells by various glycopeptides and oligosaccharides, and by studying the affinity of the immobilized lectin towards glycopeptides and oligosaccharides. Results of inhibition of hemagglutination showed that the lectin presents the highest affinity towards alpha-(1----6)-linked L-fucosyl groups. Immobilized Aleuria aurantia agglutinin interacts strongly with all N-glycosylpeptides or related glycans possessing an alpha-L-fucopyranosyl group linked to O-6 of the 2-acetamido-2-deoxy-beta-D-glucopyranosyl residue involved in the glycosylamine linkage. In addition, presence of alpha-(1----3)-linked L-fucosyl groups greatly enhances the affinity of the lectin for the alpha-(1----6)-L-fucosylated glycans. The immobilized Aleuria lectin is a powerful tool for the resolution of the microheterogeneity of L-fucosylated glycopeptides and glycans of the N-acetyl-lactosamine type.  相似文献   

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