Expeditive synthesis of trithiotriazine-cored glycoclusters and inhibition of Pseudomonas aeruginosa biofilm formation

Abstract

Readily accessible, low-valency glycoclusters based on a triazine core bearing D-galactose and L-fucose epitopes are able to inhibit biofilm formation by Pseudomonas aeruginosa. These multivalent ligands are simple to synthesize, are highly soluble, and can be either homofunctional or heterofunctional. The galactose-decorated cluster shows good affinity for Pseudomonas aeruginosa lectin lecA. They are convenient biological probes for investigating the roles of lecA and lecB in biofilm formation.

Keywords: antibiotic; biofilm; glycocluster; lectin; multivalency effect; multivalent glycosystems.

Figure 1

Previously reported low-valent glycoasterisk α-D-Man ligand based on a persulfurated benzene core [30] and currenly reported β-D-Gal compound 1.

Scheme 1

Synthesis of trivalent trithiotriazine-based glycoclusters.

Scheme 2

Synthesis of mixed triazine-based glycoclusters.

Figure 2

Dynamic light scattering experiments of bis-D-galactosyl proparyl cluster 16 with lecA. Distribution by mass for lecA + buffer (left) and lecA + 16 (200 μM, right) at 3 minute intervals. Additional experiments can be found in Supporting Information File 1.

Figure 3

Typical ITC measurements representing the raw ITC data (top) and integrated titration curves (bottom) for the binding to lecA of a) tris-D-galactosyl triazine cluster 1, and b) tris D-glucosyl glycocluster 13 (negative control).

Figure 4

Inhibition of PAO1 biofilm formation by D-galactose cluster 1, L-fucose cluster 14, and D-glucose cluster 13 (negative control). A) Biofilm growth assay in LB medium. B) Statistical analysis (above, n = 5, duplicate UV measurements) of ethanol-solubilized biofilm recovered from each well (below). C) PAO1 growth inhibition control test.