title: BEL β-trefoil: a novel lectin with antineoplastic properties in king bolete (Boletus edulis) mushrooms.
abstract: A novel lectin was purified from the fruiting bodies of king bolete mushrooms (Boletus edulis, also called porcino, cep or penny bun). The lectin was structurally characterized i.e its amino acid sequence and three-dimensional structure were determined. The new protein is a homodimer and each protomer folds as β-trefoil domain and therefore we propose the name Boletus edulis lectin (BEL) β-trefoil to distinguish it from the other lectin that has been described in these mushrooms. The lectin has potent anti-proliferative effects on human cancer cells, which confers to it an interesting therapeutic potential as an antineoplastic agent. Several crystal forms of the apoprotein and of complexes with different carbohydrates were studied by X-ray diffraction. The structure of the apoprotein was solved at 1.12 Å resolution. The interaction of the lectin with lactose, galactose, N-acetylgalactosamine and T-antigen disaccharide, Galβ1-3GalNAc, was examined in detail. All the three potential binding sites present in the β-trefoil fold are occupied in at least one crystal form and are described in detail in this paper. No important conformational changes are observed in the lectin when comparing its co-crystals with carbohydrates with those of the ligand-free protein.
authors.affiliation: Department of Biotechnology, Biocrystallography Laboratory, University of Verona, Ca Vignal 1, strada Le Grazie 15, 37134 Verona, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Bovi
authors.forename: Lucia
authors.initials: L
authors.lastname: Cenci
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Perduca
authors.forename: Stefano
authors.initials: S
authors.lastname: Capaldi
authors.forename: Maria E
authors.initials: ME
authors.lastname: Carrizo
authors.forename: Laura
authors.initials: L
authors.lastname: Civiero
authors.forename: Laurent R
authors.initials: LR
authors.lastname: Chiarelli
authors.forename: Monica
authors.initials: M
authors.lastname: Galliano
authors.forename: Hugo L
authors.initials: HL
authors.lastname: Monaco
mesh_terms: D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology; D001059:Apoproteins / Q000737:chemistry; D001487:Basidiomycota / Q000737:chemistry*; D001665:Binding Sites; D018938:Caco-2 Cells; D002241:Carbohydrates / Q000737:chemistry; D049109:Cell Proliferation / Q000187:drug effects; D018360:Crystallography, X-Ray; D005656:Fungal Proteins / Q000737:chemistry* / Q000494:pharmacology; D056945:Hep G2 Cells; D006801:Humans; D037102:Lectins / Q000737:chemistry* / Q000494:pharmacology; D061986:MCF-7 Cells; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary
chemical_list: D000970:Antineoplastic Agents; D001059:Apoproteins; D002241:Carbohydrates; D005656:Fungal Proteins; D037102:Lectins