title: Design and synthesis of high-avidity tetravalent glycoclusters as probes for Sambucus sieboldiana agglutinin and characterization of their binding properties.
abstract: We designed and synthesized three tetravalent sialo-glycoclusters that had different separations between the terminal sialic acids and the linking carboxy groups of the ethylene glycol bis(β-aminoethyl ether)-N,N,N',N'-tetraacetate scaffold to serve as ligands for the sialic acid-binding lectin Sambucus sieboldiana agglutinin (SSA). The interaction between each glycocluster and SSA was characterized by hemagglutination inhibition, quantitative precipitation, and double-diffusion assays. For the precipitation assays, the precipitin curves indicated that the ligands and SSA bound in either a 1:1 or a 1:2 ratio, i.e., stoichiometrically. The strong interactions of these sialo-glycoclusters with SSA could be ascribed to a combination of multivalency and spacer effects. We also assessed the nature of the ligand-SSA complexes by isothermal titration calorimetry and dynamic light scattering. The results of those experiments indicated that formation of intermolecular complexes occurred at less than stoichiometric ratios of ligand to SSA concentrations and that, as the concentrations of the ligands increased, larger cross-linked aggregates formed. Large aggregates that were present concurrently with visible precipitation and with a particle size centered at ~600 to 800 nm were identified by dynamic light scattering.
authors.affiliation: Department of Bioscience, Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ogata
authors.forename: Megumi
authors.initials: M
authors.lastname: Yano
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Umemura
authors.forename: Takeomi
authors.initials: T
authors.lastname: Murata
authors.forename: Enoch Y
authors.initials: EY
authors.lastname: Park
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Asai
authors.forename: Naoto
authors.initials: N
authors.lastname: Oku
authors.forename: Naoki
authors.initials: N
authors.lastname: Nakamura
authors.forename: Ichiro
authors.initials: I
authors.lastname: Matsuo
authors.forename: Taichi
authors.initials: T
authors.lastname: Usui
mesh_terms: D000085:Acetates / Q000032:analysis / Q000138:chemical synthesis* / Q000737:chemistry*; D001665:Binding Sites; D015394:Molecular Structure; D037121:Plant Lectins / Q000032:analysis* / Q000737:chemistry*; D027923:Sambucus / Q000737:chemistry*; D012794:Sialic Acids / Q000737:chemistry*
chemical_list: D000085:Acetates; D037121:Plant Lectins; D012794:Sialic Acids