A LecA Ligand Identified from a Galactoside‐Conjugate Array Inhibits Host Cell Invasion by Pseudomonas aeruginosa

Abstract

Lectin LecA is a virulence factor of Pseudomonas aeruginosa involved in lung injury, mortality, and cellular invasion. Ligands competing with human glycoconjugates for LecA binding are thus promising candidates to counteract P. aeruginosa infections. We have identified a novel divalent ligand from a focused galactoside(Gal)‐conjugate array which binds to LecA with very high affinity (Kd=82 nM). Crystal structures of LecA complexed with the ligand together with modeling studies confirmed its ability to chelate two binding sites of LecA. The ligand lowers cellular invasiveness of P. aeruginosa up to 90 % when applied in the range of 0.05–5 μM. Hence, this ligand might lead to the development of drugs against P. aeruginosa infection.

Design and Synthesis of Galactosylated Bifurcated Ligands with Nanomolar Affinity for Lectin LecA from Pseudomonas aeruginosa

“… Some bis‐galactosides that target LecA, together with their K d values (compounds G1, G2, G3 and G4).…”

“…There are a few literature examples of bis‐galactosides that display high affinity towards LecA. Three bis‐galactosides each containing a phenyl aglycon display K d values between 82 and 550 n m , corresponding to an increase in potency of between 91‐ and 159‐fold per residue (Scheme ) . The most remarkable bis‐galactosides, with increases in potency per residue between 272‐ and 3778‐fold, were those containing a rigid glucose‐triazole backbone reported by Pieters, with K d values as low as 28 n m (Scheme ) .…”

Development of Pseudomonas aeruginosa Lectin LecA Inhibitor by using Bivalent Galactosides Supported on Polyproline Peptide Scaffolds

“…(rigid dimer, 28 n m , ITC), Imberty, Römer, Winssinger et al. (glycopeptide dimer, 82 n m , ITC), and Chevolot, Morvan et al. (pyranose cluster, <20 n m , fluorescence) .…”

“…Because LecA is a tetrameric lectin and the two closest binding sites are separated by about 26 Å, various artificial scaffolds including dendrimers, clusters, and linear rigid spacers have been exploited to present galactoside ligands to the binding sites to enhance inhibition activity . In other cases, the artificial scaffolds are further functionalized to generate extra interactions with LecA for stronger binding …”

PNA‐Encoded Synthesis (PES) of a 10 000‐Member Hetero‐Glycoconjugate Library and Microarray Analysis of Diverse Lectins

“…The microarray‐based screen allows rapid identification of specific and high‐affinity glycoconjugates that are readily accessible synthetically from unprotected glycans. In a parallel report, we used this technology to home in on a potent ligand for LecA and validate the binding contribution of the linker 42. While this study did not explore higher‐order oligomers, the ability to program homo‐ or hetero‐oligomerization of nucleic acid tagged glycans has been demonstrated17, 18, 27, 42–48 and should extend the utility of these libraries.…”