Nanomolar inhibitor of the galectin-8 N-terminal domain binds via a non-canonical cation-π interaction

Purić, Edvin (author), Hassan, Mujtaba (author), Sjövall, Fredrik (author), Tomašič, Tihomir (author), Pevec, Mojca (author), Lah, Jurij (author), Adrover Forteza, Jaume (author), Sundin, Anders (author), Leffler, Hakon (author), Nilsson, Ulf (author), Logan, Derek T. (author), Anderluh, Marko (author)

Galectin-8 is a tandem-repeat galectin consisting of two distinct carbohydrate recognition domains and is a potential drug target. We have developed a library of galectin-8N inhibitors that exhibit high nanomolar Kd values as determined by a competitive fluorescence polarization assay. A detailed thermodynamic analysis of the binding of d-galactosides to galectin-8N by isothermal titration calorimetry reveals important differences in enthalpic and/or entropic contributions to binding. Contrary to expectations, the binding of 2-O-propargyl-d-galactoside was found to strongly increase the binding enthalpy, whereas the binding of 2-O-carboxymethylene-d-galactoside was surprisingly less enthalpy-driven. The results of our work suggest that the ethynyl group can successfully replace the carboxylate group when targeting the water-exposed guanidine moiety of a critical arginine residue. This results in only a minor loss of affinity and an adjusted enthalpic contribution to the overall binding due to non-canonical cation-π interactions, as evidenced by the obtained crystal structure of 2-O-propargyl-d-galactoside in complex with the N-terminal domain of galectin-8. Such an interaction has neither been identified nor discussed to date in a small-molecule ligand-protein complex.

• Language: English
• Keywords: carbohydrates, lead optimization, structure-based drug design, X-ray crystallography
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FFA - Faculty of Pharmacy
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 11 str.
• Numbering: Vol. 8, article 59
• PID: 20.500.12556/RUL-167856
• UDC: 615.4:54
• ISSN on article: 2399-3669
• DOI: 10.1038/s42004-025-01458-6
• COBISS.SI-ID: 229077763
• Publication date in RUL: 17.03.2025

Record is a part of a journal

• Title: Communications chemistry
• Shortened title: Commun. chem.
• Publisher: Macmillan Publishers, part of Springer Nature
• ISSN: 2399-3669
• COBISS.SI-ID: 529716505

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: ogljikovi hidrati, optimizacija potencialnih strank, oblikovanje zdravil na osnovi strukture, rentgenska kristalografija, farmacevtska kemija