Multivalent Glycomimetics with Affinity and Selectivity toward Fucose-Binding Receptors from Emerging Pathogens (original) (raw)
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Molecules
Series of multivalent α-l-fucoside containing glycoclusters and variously decorated l-fucosides were synthesized to find potential inhibitors of fucose-specific lectins and study the structure-binding affinity relationships. Tri- and tetravalent fucoclusters were built using copper-mediated azide-alkyne click chemistry. Series of fucoside monomers and dimers were synthesized using various methods, namely glycosylation, an azide-alkyne click reaction, photoinduced thiol-en addition, and sulfation. The interactions between compounds with six fucolectins of bacterial or fungal origin were tested using a hemagglutination inhibition assay. As a result, a tetravalent, α-l-fucose presenting glycocluster showed to be a ligand that was orders of magnitude better than a simple monosaccharide for tested lectins in most cases, which can nominate it as a universal ligand for studied lectins. This compound was also able to inhibit the adhesion of Pseudomonas aeruginosa cells to human epithelial b...
Chemistry (Weinheim an der Bergstrasse, Germany), 2018
Photorhabdus asymbiotica is a gram-negative bacterium that is not only as effective an insect pathogen as other members of the genus, but it also causes serious diseases in humans. The recently identified lectin PHL from P. asymbiotica verifiably modulates an immune response of humans and insects, which supports the idea that the lectin might play an important role in the host-pathogen interaction. Dimeric PHL contains up to seven l-fucose-specific binding sites per monomer, and in order to target multiple binding sites of PHL, α-l-fucoside-containing di-, tri- and tetravalent glycoclusters were synthesized. Methyl gallate and pentaerythritol were chosen as multivalent scaffolds, and the fucoclusters were built from the above-mentioned cores by coupling with different oligoethylene bridges and propargyl α-l-fucosides using 1,3-dipolar azide-alkyne cycloaddition. The interaction between fucoside derivates and PHL was investigated by several biophysical and biological methods, ITC and...
Synthesis and characterization of linker-armed fucose-based glycomimetics
2013
Glycomimetic molecules can be used to antagonize the action of carbohydrate-binding proteins (lectins) involved in biological processes of high relevance for human and plant disease. In this paper we describe the derivatization with appropriate linkers of a previously described glycomimetic containing an α-fucosyl amide anchor that is known to act as antagonist of the dendritic cell lectin DC-SIGN. Key steps of the functionalization were the stereoselective epoxidation of an intermediate β-amino-cyclohexene-carboxylic acid derivative, followed by regioselective opening with 2-chloroethanol. Introduction of the linker does not alter the DC-SIGN binding properties of the molecule, as shown by Surface Plasmon Resonance and NMR studies. Whereas the fu-[a5304 Scheme 4. Possible conformations of the cyclohexane ring after nucleophilic C4-opening of (a) cis epoxide 10 and (b) the hypothetical trans epoxide 13.
Chemistry – A European Journal, 2020
C-type lectin receptor (CLR) carbohydrate binding proteins found on immune cells with important functions in pathogen recognition and self and non-self-differentiation are increasingly moving into the focus of drug developers as targets for the immune therapy of cancer autoimmune diseases and inflammation and to improve the efficacy of vaccines. The development of molecules with increased affinity and selectivity over the natural glycan binders has largely focused on the synthesis of mono and disaccharide mimetics but glycan array binding experiments have shown increased binding selectivity and affinity for selected larger oligosaccharides that are able to engage in additional favorable interactions beyond the primary binding site. Here we present a platform for the rapid preparation and screening of N-glycan mimetics on microarrays that turns a panel of complex glycan core structures into structurally diverse glycomimetics by a combination of enzymatic glycosylation with a non-natural donor and subsequent cycloaddition with a collection of alkynes. All surface based reactions were monitored by MALDI-Tof MS to assess conversion and purity of spot compositions. Screening the collection of 374 N-glycomimetics against the plant lectin WFA and the 2 human immune lectins MGL and Langerin produced a number of high affinity binders as lead structures for more selective lectin targeting probes.
International Journal of Molecular Sciences
The Gram-negative bacterium Pseudomonas aeruginosa is an important opportunistic human pathogen associated with cystic fibrosis. P. aeruginosa produces two soluble lectins, the d-galactose-specific lectin PA-IL (LecA) and the l-fucose-specific lectin PA-IIL (LecB), among other virulence factors. These lectins play an important role in the adhesion to host cells and biofilm formation. Moreover, PA-IL is cytotoxic to respiratory cells in the primary culture. Therefore, these lectins are promising therapeutic targets. Specifically, carbohydrate-based compounds could inhibit their activity. In the present work, a 3-O-fucosyl lactose-containing tetravalent glycocluster was synthesized and utilized as a mutual ligand of galactophilic and fucophilic lectins. Pentaerythritol equipped with azido ethylene glycol-linkers was chosen as a multivalent scaffold and the glycocluster was constructed by coupling the scaffold with propargyl 3-O-fucosyl lactoside using an azide-alkyne 1,3-dipolar cyclo...
Organic & biomolecular chemistry, 2015
Pseudomonas aeruginosa (PA) and Burkholderia ambifaria (BA) are two opportunistic Gram negative bacteria and major infectious agents involved in lung infection of cystic fibrosis patients. Both bacteria can develop resistance to conventional antibiotherapies. An alternative strategy consists of targeting virulence factors in particular lectins with high affinity ligands such as multivalent glycoclusters. LecA (PA-IL) and LecB (PA-IIL) are two tetravalent lectins from PA that recognise galactose and fucose respectively. BambL lectin from BA is trimeric with 2 binding sites per monomer and is also specific for fucose. These three lectins are potential therapeutic targets in an anti-adhesive anti-bacterial approach. Herein, we report the synthesis of 18 oligonucleotide pentofuranose-centered or mannitol-centered glycoclusters leading to tri-, penta- or decavalent clusters with different topologies. The linker arm length between the core and the carbohydrate epitope was also varied lead...
Structure-Based Design of Glycomimetic Ligands for the N-Terminal Domain of BC2L-C Lectin
2021
The prevalence of drug-resistant infections has challenged the existing treatment regimen using antibiotics. There is a need to discover and employ alternative and complementary therapies to counteract these life threatening infections. In fast few decades, the use of anti-adhesion molecules targeting virulence factors such as lectins has been proven an attractive approach to counteract the infections by disarming the pathogens. This thesis work aimed to design glycomimetic antagonists of the N-terminal domain of the BC2L-C lectin (BC2L-C-nt) from the drug-resistant pathogen known as B. cenocepacia. We employed a fragment-based approach to design glycomimetic antagonists of the target protein (BC2L-C-nt). The initial studies were focused towards the binding site prediction and target evaluation by computational tools which identified additional druggable regions near the fucoside binding site in BC2L-C-nt. These additional regions have been explored further to evaluate the druggabil...
Multivalent glycoconjugates as anti-pathogenic agents
2013
Multivalency plays a major role in biological processes and particularly in the relationship between pathogenic microorganisms and their host that involves protein-glycan recognition. These interactions occur during the first steps of infection, for specific recognition between host and bacteria, but also at different stages of the immune response. The search for high-affinity ligands for studying such interactions involves the combination of carbohydrate head groups with different scaffolds and linkers generating multivalent glycocompounds with controlled spatial and topology parameters. By interfering with pathogen adhesion, such glycocompounds including glycopolymers, glycoclusters, glycodendrimers and glyconanoparticles have the potential to improve or replace antibiotic treatments that are now subverted by resistance. Multivalent glycoconjugates have also been used for stimulating the innate and adaptive immune systems, for example with carbohydrate-based vaccines. Bacteria present on their surfaces natural multivalent glycoconjugates such as lipopolysaccharides and S-layers that can also be exploited or targeted in anti-infectious strategies.
Insights in the rational design of synthetic multivalent glycoconjugates as lectin ligands
Organic & Biomolecular Chemistry, 2011
Much effort has been made during the last decade to design lectin inhibitors as therapeutics against viral and bacterial adhesion or to control biological functions. The chemical strategy adopted generally consists in the tethering of several binding epitopes on a common scaffold. The resulting multivalent glycoconjugates often display a much higher binding affinity for their targets compared to their monovalent counterparts, a phenomenon designed as the "cluster" or "multivalent effect". Hundreds of multimeric architectures have been designed so far and some of the compounds displayed impressive gains in binding affinity or in vivo efficiency. Progress in this area is, however, hampered by the difficulty to predict the potency of the new multimeric inhibitors. This review presents the recent efforts to probe the important structural features of the synthetic multivalent glycoconjugates for a tight binding with specific lectins. We hope that the reported examples will aid the reader to design efficient multivalent ligands in a more predictable way.