Achieving High Affinity for a Bacterial Lectin with Reversible Covalent Ligands

J Med Chem. 2024 Nov 14;67(21):19546-19560. doi: 10.1021/acs.jmedchem.4c01876. Epub 2024 Oct 31.

Abstract

High-affinity monovalent ligands for lectins are challenging to develop due to weak binding interactions. This study investigates the potential of rationally designed covalent ligands targeting the N-terminal domain of BC2L-C lectin from Burkholderia cenocepacia, a pathogen causing severe respiratory infections in immunocompromised patients. Antiadhesion therapy is emerging as a complementary approach against such infections, and bacterial lectins are suitable targets. The fucose-specific BC2L-C-Nt recognizes blood group oligosaccharides on host cells. Using a computational approach, we designed reversible covalent competitive ligands that include a fucoside anchor and a salicylaldehyde warhead targeting Lys108 near the fucose-binding site. Several candidates were synthesized and tested using competition experiments. The most effective ligand improved the IC50 of methyl-fucoside by 2 orders of magnitude, matching the affinity of the native H-type 1 trisaccharide. Control experiments confirmed the importance of both fucose anchor and salicylaldehyde moiety in the ligand's affinity. Mass analysis confirmed the covalent interaction with Lys108.

MeSH terms

  • Aldehydes / chemistry
  • Binding Sites
  • Burkholderia cenocepacia* / metabolism
  • Fucose / analogs & derivatives
  • Fucose / chemistry
  • Fucose / metabolism
  • Humans
  • Lectins / chemistry
  • Lectins / metabolism
  • Ligands

Substances

  • Ligands
  • Fucose
  • Lectins
  • Aldehydes
  • salicylaldehyde