Systematic Tuning of Fluoro-galectin-3 Interactions Provides Thiodigalactoside Derivatives with Single-Digit nM Affinity and High Selectivity.
Peterson, K., Kumar, R., Stenstrom, O., Verma, P., Verma, P.R., Hakansson, M., Kahl-Knutsson, B., Zetterberg, F., Leffler, H., Akke, M., Logan, D.T., Nilsson, U.J.(2018) J Med Chem 61: 1164-1175
- PubMed: 29284090 
- DOI: https://doi.org/10.1021/acs.jmedchem.7b01626
- Primary Citation of Related Structures:  
5OAX, 5ODY - PubMed Abstract: 
Symmetrical and asymmetrical fluorinated phenyltriazolyl-thiodigalactoside derivatives have been synthesized and evaluated as inhibitors of galectin-1 and galectin-3. Systematic tuning of the phenyltriazolyl-thiodigalactosides' fluoro-interactions with galectin-3 led to the discovery of inhibitors with exceptional affinities (K d down to 1-2 nM) in symmetrically substituted thiodigalactosides as well as unsurpassed combination of high affinity (K d 7.5 nM) and selectivity (46-fold) over galectin-1 for asymmetrical thiodigalactosides by carrying one trifluorphenyltriazole and one coumaryl moiety. Studies of the inhibitor-galectin complexes with isothermal titration calorimetry and X-ray crystallography revealed the importance of fluoro-amide interaction for affinity and for selectivity. Finally, the high affinity of the discovered inhibitors required two competitive titration assay tools to be developed: a new high affinity fluorescent probe for competitive fluorescent polarization and a competitive ligand optimal for analyzing high affinity galectin-3 inhibitors with competitive isothermal titration calorimetry.
Organizational Affiliation: 
Centre for Analysis and Synthesis, Department of Chemistry, Lund University , Box 124, SE-221 00 Lund, Sweden.