title: Structural requirements of carbohydrates to bind Agaricus bisporus lectin.
abstract: Galbeta1-3GalNAc (T-disaccharide) and related molecules were assayed to describe the structural requirements of carbohydrates to bind Agaricus bisporus lectin (ABL). Results provide insight into the most relevant regions of T-disaccharide involved in the binding of ABL. It was found that monosaccharides bind ABL weakly indicating a more extended carbohydrate-binding site as compared to those involvedin the T-disaccharide specific lectins such as jacalin and peanut agglutinin. Lacto-N-biose (Galbeta1-3GlcNAc) unlike T-disaccharide, is unable to inhibit the ABL interaction, thus showing the great importance of the position of the axial C-4 hydroxyl group of GalNAc in T-disaccharide. This finding could explain the inhibitory ability of Galbeta1-6GlcNAc and lactose because C-4 and C-3 hydroxyl groups of reducing Glc, respectively, occupy a similar position as reported by conformational analysis. From the comparison of different glycolipids bearing terminal T-disaccharide bound to different linkages, it can be seen than ABL binding is even more impaired by an adjacent C-6 residual position than by the anomeric influence of T-disaccharide. Furthermore, the addition of beta-GlcNAc to the terminal T-disaccharide in C-3 position of Gal does not affect the ABL binding whereas if an anionic group such as glucuronic acid is added to C-3, the binding is partially affected. These findings demonstrate that ABL holds a particular binding nature different from that of other T-disaccharide specific lectins.
authors.affiliation: Departamento de Bioquímica Clínica and Departamento de Química Biológica-CIQUIBIC-CONICET, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Agencia Postal 4, CC 61, 5000 Córdoba, Argentina.
authors.forename: F J
authors.initials: FJ
authors.lastname: Irazoqui
authors.forename: M A
authors.initials: MA
authors.lastname: Vides
authors.forename: G A
authors.initials: GA
authors.lastname: Nores
mesh_terms: D001665:Binding Sites; D002236:Carbohydrate Conformation; D050260:Carbohydrate Metabolism; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004187:Disaccharides / Q000737:chemistry / Q000378:metabolism; D037102:Lectins / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009195:Peroxidase / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: C041433:Agaricus lectins; D002241:Carbohydrates; D004187:Disaccharides; D037102:Lectins; D009195:Peroxidase