title: Amino acid sequence and three-dimensional structure of the Tn-specific isolectin B4 from Vicia villosa.
abstract: The partial amino acid sequence of the tetrameric isolectin B4 from Vicia villosa seeds has been determined by peptide analysis, and its three-dimensional structure solved by molecular replacement techniques and refined at 2.9 A resolution to a crystallographic R-factor of 21%. Each subunit displays the thirteen-stranded beta-barrel topology characteristic of legume lectins. The amino acid residues involved in metal- and sugar-binding are similar to those of other GalNAc-specific lectins, indicating that residues outside the carbohydrate-binding pocket modulate the affinity for the Tn glycopeptide. Isolectin B4 displays an unusual quaternary structure, probably due to protein glycosylation.
authors.affiliation: Dept de Bioquímica, Facultad de Medicina, Montevideo, Uruguay.
authors.forename: E
authors.initials: E
authors.lastname: Osinaga
authors.forename: D
authors.initials: D
authors.lastname: Tello
authors.forename: C
authors.initials: C
authors.lastname: Batthyany
authors.forename: M
authors.initials: M
authors.lastname: Bianchet
authors.forename: G
authors.initials: G
authors.lastname: Tavares
authors.forename: R
authors.initials: R
authors.lastname: Durán
authors.forename: C
authors.initials: C
authors.lastname: Cerveñansky
authors.forename: L
authors.initials: L
authors.lastname: Camoin
authors.forename: A
authors.initials: A
authors.lastname: Roseto
authors.forename: P M
authors.initials: PM
authors.lastname: Alzari
mesh_terms: D000595:Amino Acid Sequence; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000378:metabolism*; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D007887:Fabaceae / Q000737:chemistry*; D037102:Lectins / Q000737:chemistry* / Q000378:metabolism; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D037121:Plant Lectins; D010946:Plants, Medicinal; D017433:Protein Structure, Secondary
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; D037102:Lectins; D046911:Macromolecular Substances; D037121:Plant Lectins; C040286:Tn antigen