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Combining Glycomimetic and Multivalent Strategies toward Designing Potent Bacterial Lectin Inhibitors
Author(s) -
Chabre Yoann M.,
Giguère Denis,
Blanchard Bertrand,
Rodrigue Jacques,
Rocheleau Sylvain,
Neault Mathieu,
Rauthu Subhash,
Papadopoulos Alex,
Arnold Alexandre A.,
Imberty Anne,
Roy René
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201003402
Subject(s) - isothermal titration calorimetry , chemistry , galactosides , glycoconjugate , dissociation constant , molecular binding , combinatorial chemistry , conjugate , docking (animal) , avidity , stereochemistry , galectin , lectin , click chemistry , bioorthogonal chemistry , glycosylation , biochemistry , molecule , glycoside , organic chemistry , medicine , mathematical analysis , receptor , mathematics , nursing , antibody , immunology , biology
As part of ongoing activities toward the design of potent and selective ligands against galactoside‐binding proteins from animal, bacterial, and plant lectins, a systematic investigation involving the synthesis and binding evaluations of a series of original β‐ C ‐galactopyranoside mimetics is described. The multivalent presentation of partly optimized candidates on various dendritic scaffolds through Cu I ‐catalyzed azide–alkyne cycloaddition (CuAAc) has also been achieved. Biophysical investigations based on isothermal titration calorimetry (ITC) have indicated a dissociation constant in the low micromolar range for the best optimized monovalent conjugate ( K d =37 μ M ). The results thus confirmed that stable C ‐galactosides could represent efficient synthetic glycomimetics of natural α‐linked oligosaccharidic inhibitors of PA‐IL lectin (Lec A) from the pathogenic Pseudomonas aeruginosa . Striking enhancements in the avidity of the glycoconjugates were also observed for tri‐, hexa‐, and nonavalent derivatives, among which the most potent exhibited dissociation constants below 500 n M , corresponding to a 400‐fold increase in affinity compared with the β‐ D ‐Gal‐ O ‐Me used as reference. To deepen our understanding of the binding mode of the best glycomimetics involved in the recognition process, molecular modeling studies, docking calculations, and NMR diffusion measurements have been performed. Although favorable complementary interactions induced by the addition of the hydrophobic aglycon might explain the affinity enhancement, experimental determination of the size and the topology of the multivalent conjugates further supported the formation of aggregative complexes as a major multivalent binding mode. This work represents a systematic and comprehensive study towards a thorough understanding of the protein–carbohydrate interactions involved in Pseudomonas aeruginosa infection, and as such should prove useful for the development of stable and optimized anti‐adhesive agents.