Engineering the ligand specificity of the human galectin-1 by incorporation of tryptophan analogs

Felix Tobola (1, 2) , Martin Lepšík (3) , Syeda Rehana Zia (4) , Hakon Leffler (5) , Ulf J Nilsson (5) , Ola Blixt (6) , Anne Imberty (3) , Birgit Wiltschi (1)

1 ACIB - Austrian Centre of Industrial Biotechnology GmbH
2 TU Graz - Graz University of Technology [Graz]
3 CERMAV - Centre de Recherches sur les Macromolécules Végétales
4 University of Karachi
5 Skane University Hospital [Lund]
6 DTU - Danmarks Tekniske Universitet = Technical University of Denmark

Galectin-1 is a β-galactoside-binding lectin with manifold biological functions. A single tryptophan residue (W68) in its carbohydrate binding site plays a major role in ligand binding and is highly conserved among galectins. To fine tune galectin-1 specificity, we introduced several non-canonical tryptophan analogs at this position of human galectin-1 and analyzed the resulting variants using glycan microarrays. Two variants containing 7-azatryptophan and 7fluorotryptophan showed a reduced affinity for 3'-sulfated oligosaccharides. Their interaction with different ligands was further analyzed by fluorescence polarization competition assay. Using molecular modeling we provide structural clues that the change in affinities comes from modulated interactions and solvation patterns. Thus, we show that the introduction of subtle atomic mutations in the ligand binding site of galectin-1 is an attractive approach for finetuning its interactions with different ligands.

Mots clés: Lectin; carbohydrates; glycoconjugate; glycomimetics; LecA

Domaines: Biologie structurale [q-bio.BM]

Felix Tobola, Martin Lepšík, Syeda Rehana Zia, Hakon Leffler, Ulf J Nilsson, et al.. Engineering the ligand specificity of the human galectin-1 by incorporation of tryptophan analogs. ChemBioChem, 2022, 23 (5), pp.e202100593. ⟨10.1002/cbic.202100593⟩. ⟨hal-03517502⟩