LecA (PA-IL) from Pseudomonas aeruginosa linked to Fluorescein

LecA (PA-IL) from Pseudomonas aeruginosa linked to Fluorescein LecA (PA-IL) from Pseudomonas aeruginosa linked to Fluorescein is a fluorescently labeled lectin used to study bacterial adhesion mechanisms, biofilm formation, and host-pathogen interactions. This conjugate enables real-time visualization of galactose-specific binding events in experimental systems. Key Characteristics of LecA (PA-IL): Function : LecA is a tetrameric, calcium-dependent lectin that binds α-galactose residues on host glycosphingolipids. It facilitates bacterial adhesion to epithelial cells, promotes biofilm formation, and contributes to cytotoxicity during infections. Disrupts lung epithelial barrier function, increasing permeability and bacterial dissemination. Acts as a virulence factor in chronic infections like cystic fibrosis. Structural Features : Molecular weight: ~12.8 kDa (monomer). Contains a carbohydrate-binding site with conserved tryptophan residues (e.g., W42) critical for galactose recognition. Requires Ca²⁺ ions for structural stability and ligand binding. Fluorescein Conjugation : The fluorescein tag allows quantitative tracking of LecA interactions with galactose-containing substrates. Applications include: Fluorescence polarization assays for ligand affinity measurements. Imaging bacterial adhesion to host tissues. High-throughput screening of glycomimetic inhibitors. Applications in Research: Biofilm Studies : LecA stabilizes biofilms by crosslinking extracellular polysaccharides (e.g., Psl). Fluorescein-labeled LecA helps monitor biofilm architecture and inhibitor efficacy. Drug Discovery : Used to identify non-carbohydrate inhibitors via NMR-based methods (e.g., protein-observed ¹⁹F NMR). Glycoclusters with β-d-galactoside ligands show anti-adhesion potential by blocking LecA-mediated binding. Pathogenesis Analysis : In vivo studies demonstrate that LecA inhibition with α-methyl-galactoside reduces lung injury and bacterial load. Production and Validation: Recombinantly expressed in E. coli with affinity purification. Functional activity post-labeling confirmed via: Calcium-dependent binding assays. Structural integrity checks using X-ray crystallography. This tool is vital for advancing therapeutic strategies targeting LecA-mediated infections, particularly in antibiotic-resistant P. aeruginosa strains. Citations: https://pubmed.ncbi.nlm.nih.gov/32573695/ https://experiments.springernature.com/articles/10.1007/978-1-0716-0430-4_25 https://pmc.ncbi.nlm.nih.gov/articles/PMC7874386/ https://pmc.ncbi.nlm.nih.gov/articles/PMC6920806/ https://journals.asm.org/doi/full/10.1128/iai.01204-08 https://pmc.ncbi.nlm.nih.gov/articles/PMC2681743/