title: High-mannose N-glycan-specific lectin from the red alga Kappaphycus striatum (Carrageenophyte).
abstract: From a fresh sample (1 kg) of cultivated red alga Kappaphycus striatum, three isolectins, KSA-1 (15.1 mg), KSA-2 (58.0 mg) and KSA-3 (6.9 mg), were isolated by a combination of extraction with aqueous ethanol, ethanol precipitation, and ion exchange chromatography. Isolated KSAs were monomeric proteins of about 28kDa having identical 20N-terminal amino acid sequences to each other. Their hemagglutination activities were not inhibited by monosaccharides, but inhibited by glycoproteins bearing high-mannose N-glycans. In a binding experiment with pyridylaminated oligosaccharides by centrifugal ultrafiltration-HPLC assay, the isolectin KSA-2 was exclusively bound to high-mannose type N-glycans, but not to other glycans. Including complex types and a pentasaccharide core of N-glycans, indicating that it recognized branched oligomannosides. The binding activity of KSA-2 was slightly different among high-mannose N-glycans examined, indicating that the lectin has a higher affinity for those having the exposed (α1-3) Man in the D2 arm. On the other hand, KSA-2 did not bind to a free oligomannose that is a constituent of the branched oligomannosides, implying that the portion of the core GlcNAc residue(s) of the N-glycans is also essential for binding. Thus, KSA-2 appears to recognize the extended carbohydrate structure with a minimal length of a tetrasaccharide, Man(α1-3)Man(α1-6)Man(β1-4)GlcNAc. This study indicates that K. striatum, which has extensively been cultivated as a source of carrageenan, is a good source of a valuable lectin(s) that is strictly specific for high-mannose N-glycans.
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi - Hiroshima 739-8528, Japan; Nhatrang Institute of Technology Research and Application, 2A-Hungvuong Street, Nhatrang City, Khanhhoa Province, Viet Nam.
authors.forename: Le Dinh
authors.initials: le D
authors.lastname: Hung
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi - Hiroshima 739-8528, Japan; Faculty of Pharmacy, Yasuda Women's University, 6-13-1 Yasuhigashi, Asaminami, Hiroshima 731-0153, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi - Hiroshima 739-8528, Japan.
authors.forename: Kanji
authors.initials: K
authors.lastname: Hori
mesh_terms: D000818:Animals; D002240:Carbohydrate Sequence; D006023:Glycoproteins / Q000737:chemistry; D006384:Hemagglutination; D006801:Humans; D037241:Mannose-Binding Lectins / Q000737:chemistry*; D009005:Monosaccharides / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry; D000461:Rhodophyta / Q000737:chemistry*
chemical_list: D006023:Glycoproteins; D037241:Mannose-Binding Lectins; D009005:Monosaccharides; D011134:Polysaccharides