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Combining Glycomimetic and Multivalent Strategies toward Designing Potent Bacterial Lectin Inhibitors

Authors

  • Dr. Yoann M. Chabre,

    1. Pharmaqam, Department of Chemistry, Université du Québec à Montréal, P.O. Box 8888, Succ. Centre-Ville, Montreal, Québec, H3C 3P8 (Canada), Fax: (+1) 514-987-4054
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  • Dr. Denis Giguère,

    1. Pharmaqam, Department of Chemistry, Université du Québec à Montréal, P.O. Box 8888, Succ. Centre-Ville, Montreal, Québec, H3C 3P8 (Canada), Fax: (+1) 514-987-4054
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  • Dr. Bertrand Blanchard,

    1. CERMAV CNRS (Affiliated to Université Joseph Fourier and belonging to ICMG), BP 53, 38041 Grenoble cedex 9 (France), Fax: (+33) 476-547-203
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  • Jacques Rodrigue,

    1. Pharmaqam, Department of Chemistry, Université du Québec à Montréal, P.O. Box 8888, Succ. Centre-Ville, Montreal, Québec, H3C 3P8 (Canada), Fax: (+1) 514-987-4054
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  • Sylvain Rocheleau,

    1. Pharmaqam, Department of Chemistry, Université du Québec à Montréal, P.O. Box 8888, Succ. Centre-Ville, Montreal, Québec, H3C 3P8 (Canada), Fax: (+1) 514-987-4054
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  • Mathieu Neault,

    1. Pharmaqam, Department of Chemistry, Université du Québec à Montréal, P.O. Box 8888, Succ. Centre-Ville, Montreal, Québec, H3C 3P8 (Canada), Fax: (+1) 514-987-4054
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  • Subhash Rauthu,

    1. Pharmaqam, Department of Chemistry, Université du Québec à Montréal, P.O. Box 8888, Succ. Centre-Ville, Montreal, Québec, H3C 3P8 (Canada), Fax: (+1) 514-987-4054
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  • Alex Papadopoulos,

    1. Pharmaqam, Department of Chemistry, Université du Québec à Montréal, P.O. Box 8888, Succ. Centre-Ville, Montreal, Québec, H3C 3P8 (Canada), Fax: (+1) 514-987-4054
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  • Dr. Alexandre A. Arnold,

    1. Pharmaqam, Department of Chemistry, Université du Québec à Montréal, P.O. Box 8888, Succ. Centre-Ville, Montreal, Québec, H3C 3P8 (Canada), Fax: (+1) 514-987-4054
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  • Dr. Anne Imberty,

    Corresponding author
    1. CERMAV CNRS (Affiliated to Université Joseph Fourier and belonging to ICMG), BP 53, 38041 Grenoble cedex 9 (France), Fax: (+33) 476-547-203
    • CERMAV CNRS (Affiliated to Université Joseph Fourier and belonging to ICMG), BP 53, 38041 Grenoble cedex 9 (France), Fax: (+33) 476-547-203
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  • Prof. René Roy

    Corresponding author
    1. Pharmaqam, Department of Chemistry, Université du Québec à Montréal, P.O. Box 8888, Succ. Centre-Ville, Montreal, Québec, H3C 3P8 (Canada), Fax: (+1) 514-987-4054
    • Pharmaqam, Department of Chemistry, Université du Québec à Montréal, P.O. Box 8888, Succ. Centre-Ville, Montreal, Québec, H3C 3P8 (Canada), Fax: (+1) 514-987-4054
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Abstract

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 CuI-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 (Kd=37 μM). 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 nM, 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.

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