Aleuria aurantia lectin exhibits antifungal activity against Mucor racemosus.

Aleuria aurantia lectin (AAL) is an L-fucose-specific lectin produced in the mycelia and fruit-bodies of the widespread ascomycete fungus Aleuria aurantia. It is extensively used in the detection of fucose, but its physiological role remains unknown. To investigate this, we analyzed the interaction between AAL and, a zygomycete fungus Mucor racemosus, which is assumed to contain fucose in its cell wall.

Molecular structure and properties of lectin from tomato fruit.

A cDNA encoding tomato fruit lectin was cloned from an unripe cherry-tomato fruit cDNA library. The isolated lectin cDNA contained an open reading frame encoding 365 amino acids, including peptides that were sequenced. The deduced sequence consisted of three distinct domains: (i) an N-terminal short extensin-like domain; (ii) a Cys-rich carbohydrate binding domain composed of four almost identical chitin-binding domains; (iii) an internal extensin-like domain of 101 residues containing 15 SerPro(4) motifs inserted between the first and second chitin-binding domains.

Focused differential glycan analysis with the platform antibody-assisted lectin profiling for glycan-related biomarker verification.

Protein glycosylation is a critical subject attracting increasing attention in the field of proteomics as it is expected to play a key role in the investigation of histological and diagnostic biomarkers. In this context, an enormous number of glycoproteins have now been nominated as disease-related biomarkers. However, there is no appropriate strategy in the current proteome platform to qualify such marker candidate molecules, which relates their specific expression to particular diseases.

Engineering of mucin-type human glycoproteins in yeast cells.

Mucin-type O-glycans are the most typical O-glycans found in mammalian cells and assume many different biological roles. Here, we report a genetic engineered yeast strain capable of producing mucin-type sugar chains. Genes encoding Bacillus subtilis UDP-Gal/GalNAc 4-epimerase, human UDP-Gal/GalNAc transporter, human ppGalNAc-T1, and Drosophila melanogaster core1 beta1-3 GalT were introduced into Saccharomyces cerevisiae.

Functional glycosylation of human podoplanin: glycan structure of platelet aggregation-inducing factor.

Podoplanin (Aggrus) is a mucin-type sialoglycoprotein that plays a key role in tumor cell-induced platelet aggregation. Podoplanin possesses a platelet aggregation-stimulating (PLAG) domain, and Thr52 in the PLAG domain of human podoplanin is important for its activity. Endogenous or recombinant human podoplanin were purified, and total glycosylation profiles were surveyed by lectin microarray.

Inhibition of tumor cell-induced platelet aggregation using a novel anti-podoplanin antibody reacting with its platelet-aggregation-stimulating domain.

The mucin-type sialoglycoprotein, podoplanin (aggrus), is a platelet-aggregating factor on cancer cells. We previously described up-regulated expression of podoplanin in malignant astrocytic tumors including glioblastoma. Its expression was associated with tumor malignancy.

Production of fruiting-body lectins of Pleurotus cornucopiae in methylotrophic yeast Pichia pastoris.

Fruiting-body lectin genes obtained from Pleurotus cornucopiae were expressed in Pichia pastoris Because of glycosylation of the products, their molecular mass was larger than that of the corresponding native lectins. They showed binding activity to porcine stomach mucin in the enzyme-linked lectin assay system, but did not agglutinate red blood cells.

Properties of mycelial aggregate-specific lectin of Pleurotus cornucopiae produced in Pichia pastoris.

cDNA of a mycelial aggregate-specific lectin of Pleurotus cornucopiae was expressed in Pichia pastoris, and the expression product was purified and characterized. The product was functional, and the hemagglutinating activity was inhibited most strongly by the addition of N-acetyl-D-galactosamine as was the native lectin. The native lectin is a glycoprotein having five glycosylation recognition signals, and the expression product showed slightly larger molecular mass than that of the native one due to further glycosylation.

Involvement of tyrosines at fucose-binding sites of Aleuria aurantia lectin: non-equal response to site-directed mutagenesis among five sites.

Since the involvement of Tyr residues in the fucose-binding of Aleuria aurantia lectin (AAL) was proved by chemical modification using the Tyr-specific reagent tetranitromethane, site-directed mutagenesis was attempted. Since the tertiary structure of AAL was determined recently to be a six-bladed beta-propeller fold, and five fucose-binding sites per subunit were found, based on positions of Tyr residues in the tertiary structure, three classes of mutants were constructed: 1) Tyr on the 2nd beta-strand of each blade (beta-2 mutants), 2) Tyr or Trp on the 3rd beta-strand (beta-3 mutants), and 3) Tyr outside of binding sites (other-Y mutants). The mutagenized cDNA was expressed in Escherichia coli as His-tag-AAL, and the hemagglutinating activity was assayed.

Production of functional lectin in Pichia pastoris directed by cloned cDNA from Aleuria aurantia.

A plasmid bearing a nucleotide sequence of fucose-specific lectin of Aleuria aurantia was constructed and expressed in a methylotrophic yeast, Pichia pastoris. The product showed almost the same hemagglutinating activity as the lectin produced in Escherichia coli, the properties of which were quite similar to the native one. Because of glycosylation of the product, the molecular mass was larger than that of the native one, and it acquired higher thermostability.

Purification and properties of a lectin from ascomycete mushroom, Ciborinia camelliae.

A lectin was isolated from an ascomycete mushroom, Ciborinia camelliae which was specific to N-acetyl-D-galactosamine. On SDS-polyacrylamide gel electrophoresis; this lectin gave a single band of approximately 17-kDa in the presence of 2-mercaptoethanol, but formed dimers, trimers and tetramers in its absence. Amino acid analysis revealed the lectin contained two cysteines and no methionine.