BC2LA from Burkholderia cenocepacia linked to Fluorescein

BC2LA from Burkholderia cenocepacia linked to Fluorescein

BC2L-A from Burkholderia cenocepacia linked to Fluorescein is a fluorescently labeled calcium-dependent (C-type) lectin used to study bacterial adhesion, biofilm dynamics, and carbohydrate interactions in the context of cystic fibrosis (CF) and chronic infections. This lectin is critical for understanding B. cenocepacia virulence and developing anti-infective therapies.

Key Characteristics of BC2L-A:

• Function:
  BC2L-A is a mannose/heptose-specific lectin essential for biofilm structural integrity under flow conditions. It facilitates bacterial aggregation and stabilizes extracellular polysaccharides (e.g., LPS core heptoses) through calcium-dependent binding. Unlike its homolog LecB (Pseudomonas aeruginosa), BC2L-A exhibits strict selectivity for the C6 hydroxyl group of D-mannose, making it indispensable for high-affinity ligand interactions.
• Structural Features:
  • Molecular weight: ~12–14 kDa (monomer), forming functional dimers.
  • Contains a LecB-like domain with calcium-coordinated binding sites for α-D-mannose and L-glycero-D-manno-heptose.
  • Structural integrity depends on conserved residues (e.g., W42) for carbohydrate recognition.
• Fluorescein Conjugation:
  Labeled with fluorescein 5-isothiocyanate (FITC), BC2L-A enables:
  • Real-time tracking of mannose/heptose-binding interactions via fluorescence polarization assays.
  • Quantitative analysis of biofilm architecture under flow conditions.
  • High-throughput screening of glycomimetic inhibitors targeting its carbohydrate-binding site.

Applications in Research:

1. Biofilm Studies:
   BC2L-A stabilizes biofilms by crosslinking bacterial LPS heptoses, critical for maintaining structural integrity in dynamic environments. Fluorescein labeling allows visualization of biofilm matrix organization and inhibitor efficacy.
2. Inhibitor Development:
   • BC2L-A’s strict requirement for the C6 hydroxyl guides the design of mannoheptose derivatives (e.g., (6S)-mannoheptose) as potent inhibitors.
   • Competitive binding assays reveal diastereoselectivity, aiding in optimizing inhibitor specificity.
3. Host-Pathogen Interactions:
   Investigates BC2L-A’s role in bacterial adhesion to host glycans and LPS-mediated immune evasion.

Regulation and Production:

• Co-regulated by quorum sensing (BDSF and AHL systems) and expressed in a lectin cluster (bclACB) with BC2L-B/C.
• Recombinantly produced in E. coli and validated via calcium-dependent binding assays.

This tool is pivotal for advancing anti-virulence strategies against B. cenocepacia, particularly in CF-related infections where biofilm persistence and antibiotic resistance are major challenges.

Citations:

1. https://academic.oup.com/glycob/article-pdf/22/10/1387/16655387/cws105.pdf
2. https://pubmed.ncbi.nlm.nih.gov/21909279/
3. https://pubs.rsc.org/de/content/getauthorversionpdf/C5MD00557D
4. https://pmc.ncbi.nlm.nih.gov/articles/PMC3164656/
5. https://academic.oup.com/glycob/article/22/10/1387/1988347
6. https://pubs.rsc.org/en/content/articlelanding/2016/md/c5md00557d
7. https://www.elicityl-oligotech.com/free-lectins/579-bc2la-from-burkholderia-cenocepacia—bacterial-protein-produced-in-e–coli.html
8. https://pubmed.ncbi.nlm.nih.gov/22763039/
9. https://www.rcsb.org/structure/4aoc
10. https://pmc.ncbi.nlm.nih.gov/articles/PMC2168628/