title: Multimeric lactoside "click clusters" as tools to investigate the effect of linker length in specific interactions with peanut lectin, galectin-1, and -3.
abstract: Multimeric lactosides based on carbohydrate scaffolds with valencies ranging from 1 to 4 and different linker lengths were synthesized by a copper-catalyzed azide-alkyne cycloaddition (CuAAC). The binding affinities and crosslinking abilities of the new "click clusters" toward biologically relevant galectins (gal-1, gal-3) and peanut lectin were evaluated by fluorescent polarization assay (FPA) and enzyme-linked lectin assay (ELLA), respectively. FPA indicated that the binding affinities of the synthetic multilactosides towards the galectins increased proportionally with their lactosyl content, without significant differences due to the spacer length. ELLA evidenced a modest cluster effect for the multivalent conjugates, with a relative potency per lactoside ranging from 2.1 to 3.2. Nearly identical binding affinities were recorded for derivatives differing in the length of the linkers, in agreement with the FPA data. These results demonstrate that this parameter does not significantly influence the recognition process when interactions occur at a single lectin site. Molecular dynamics revealed that glycoconjugates adopt a pseudoglobular structure with a random localization of the lactoside residues. These spatial distributions were observed irrespective of the linker length; this explains the virtually equal affinities recorded by ELLA. In contrast, two-site "sandwich" ELLA clearly revealed that multivalent derivatives bearing the longest spacers were more efficient for crosslinking lectins. Intrinsic affinities, devoid of aggregation effects, and crosslinking capabilities are, therefore, not directly related phenomena that must be taking into consideration in neoglycoconjugate design for specific applications.
authors.affiliation: Department of Chemistry and UFR of Pharmacy, Laboratoire des Glucides UMR CNRS 6219, Institut de Chimie de Picardie, Université de Picardie Jules Verne, 80039 Amiens Cedex 1 France. sebastien.gouin@u-picardie.fr
authors.forename: Sébastien G
authors.initials: SG
authors.lastname: Gouin
authors.forename: José Manuel
authors.initials: JM
authors.lastname: García Fernández
authors.forename: Enguerran
authors.initials: E
authors.lastname: Vanquelef
authors.forename: François-Yves
authors.initials: FY
authors.lastname: Dupradeau
authors.forename: Emma
authors.initials: E
authors.lastname: Salomonsson
authors.forename: Hakon
authors.initials: H
authors.lastname: Leffler
authors.forename: Mariano
authors.initials: M
authors.lastname: Ortega-Muñoz
authors.forename: Ulf J
authors.initials: UJ
authors.lastname: Nilsson
authors.forename: José
authors.initials: J
authors.lastname: Kovensky
mesh_terms: D000480:Alkynes / Q000737:chemistry; D010367:Arachis / Q000378:metabolism; D001386:Azides / Q000737:chemistry; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D057075:Enzyme Assays; D016231:Fluorescence Polarization Immunoassay; D037483:Galectin 1 / Q000737:chemistry*; D037502:Galectin 3 / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D019887:Peanut Agglutinin / Q000737:chemistry*
chemical_list: D000480:Alkynes; D001386:Azides; D037483:Galectin 1; D037502:Galectin 3; D006027:Glycosides; D019887:Peanut Agglutinin; C008245:lactosides; D003300:Copper