title: Toxic isolectins from the mushroom Boletus venenatus.
abstract: Ingestion of the toxic mushroom Boletus venenatus causes a severe gastrointestinal syndrome, such as nausea, repetitive vomiting, diarrhea, and stomachache. A family of isolectins (B. venenatus lectins, BVLs) was isolated as the toxic principles from the mushroom by successive 80% ammonium sulfate-precipitation, Super Q anion-exchange chromatography, and TSK-gel G3000SW gel filtration. Although BVLs showed a single band on SDS-PAGE, they were further divided into eight isolectins (BVL-1 to -8) by BioAssist Q anion-exchange chromatography. All the isolectins showed lectin activity and had very similar molecular weights as detected by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis. Among them, BVL-1 and -3 were further characterized with their complete amino acid sequences of 99 amino acids determined and found to be identical to each other. In the hemagglutination inhibition assay, both proteins failed to bind to any mono- or oligo-saccharides tested and showed the same sugar-binding specificity to glycoproteins. Among the glycoproteins examined, asialo-fetuin was the strongest inhibitor. The sugar-binding specificity of each isolectin was also analyzed by using frontal affinity chromatography and surface plasmon resonance analysis, indicating that they recognized N-linked sugar chains, especially Galbeta1-->4GlcNAcbeta1-->4Manbeta1-->4GlcNAcbeta1-->4GlcNAc (Type II) residues in N-linked sugar chains. BVLs ingestion resulted in fatal toxicity in mice upon intraperitoneal administration and caused diarrhea upon oral administration in rats.
authors.affiliation: Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Suruga-ku, Shizuoka, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Horibe
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Hideo
authors.initials: H
authors.lastname: Dohra
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Morita
authors.forename: Takeomi
authors.initials: T
authors.lastname: Murata
authors.forename: Taichi
authors.initials: T
authors.lastname: Usui
authors.forename: Sachiko
authors.initials: S
authors.lastname: Nakamura-Tsuruta
authors.forename: Masugu
authors.initials: M
authors.lastname: Kamei
authors.forename: Jun
authors.initials: J
authors.lastname: Hirabayashi
authors.forename: Masanori
authors.initials: M
authors.lastname: Matsuura
authors.forename: Mina
authors.initials: M
authors.lastname: Yamada
authors.forename: Yoko
authors.initials: Y
authors.lastname: Saikawa
authors.forename: Kimiko
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Masaya
authors.initials: M
authors.lastname: Nakata
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kawagishi
mesh_terms: D000363:Agaricales / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D001212:Asialoglycoproteins; D002241:Carbohydrates / Q000737:chemistry; D003967:Diarrhea / Q000139:chemically induced; D004591:Electrophoresis, Polyacrylamide Gel; D060748:Fetuins; D006023:Glycoproteins / Q000737:chemistry; D037102:Lectins / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity; D051379:Mice; D009183:Mycotoxins / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity; D037121:Plant Lectins / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity; D051381:Rats; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D000509:alpha-Fetoproteins
chemical_list: D001212:Asialoglycoproteins; D002241:Carbohydrates; D060748:Fetuins; D006023:Glycoproteins; D037102:Lectins; D009183:Mycotoxins; D037121:Plant Lectins; D000509:alpha-Fetoproteins; C017029:asialofetuin