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Slow diffusion of lactose out of galectin-3 crystals monitored by X-ray crystallography: Possible implications for ligand-exchange protocols

Journal Article


Abstract


  • Galectin-3 is a multifunctional carbohydrate-binding protein that has roles in cancer progression. In addition to carbohydrate-dependent extracellular functions, galectin-3 participates in carbohydrate-independent intracellular signalling pathways, including apoptosis, via protein-protein interactions, some of which engage the carbohydrate-binding groove. When ligands bind within this site, conformational rearrangements are induced and information on unliganded galectin-3 is therefore valuable for structure-based drug design. Removal of cocrystallized lactose from the human galectin-3 carbohydrate-recognition domain was achieved via crystal soaking, but took weeks despite low affinity. Pre-soaking to remove lactose enabled the subsequent binding of cryoprotectant glycerol, whereas when the lactose was not removed a priori the glycerol could not displace it in the short cryosoaking time frame. This slow diffusion of lactose out of the crystals contrasts with the entrance of glycerol, which takes place within minutes. The importance of the removal of incumbent ligands prior to attempts to introduce alternative ligands is indicated, even for proteins exhibiting low affinity for ligands, and has significance for ligand exchange in structure-based drug design. © International Union of Crystallography 2007.

UOW Authors


  •   Blanchard, Helen (external author)

Publication Date


  • 2007

Citation


  • Collins, P. M., Hidari, K. I. P. J., & Blanchard, H. (2007). Slow diffusion of lactose out of galectin-3 crystals monitored by X-ray crystallography: Possible implications for ligand-exchange protocols. Acta Crystallographica Section D: Biological Crystallography, 63(3), 415-419. doi:10.1107/S090744490605270X

Scopus Eid


  • 2-s2.0-33947301415

Start Page


  • 415

End Page


  • 419

Volume


  • 63

Issue


  • 3

Abstract


  • Galectin-3 is a multifunctional carbohydrate-binding protein that has roles in cancer progression. In addition to carbohydrate-dependent extracellular functions, galectin-3 participates in carbohydrate-independent intracellular signalling pathways, including apoptosis, via protein-protein interactions, some of which engage the carbohydrate-binding groove. When ligands bind within this site, conformational rearrangements are induced and information on unliganded galectin-3 is therefore valuable for structure-based drug design. Removal of cocrystallized lactose from the human galectin-3 carbohydrate-recognition domain was achieved via crystal soaking, but took weeks despite low affinity. Pre-soaking to remove lactose enabled the subsequent binding of cryoprotectant glycerol, whereas when the lactose was not removed a priori the glycerol could not displace it in the short cryosoaking time frame. This slow diffusion of lactose out of the crystals contrasts with the entrance of glycerol, which takes place within minutes. The importance of the removal of incumbent ligands prior to attempts to introduce alternative ligands is indicated, even for proteins exhibiting low affinity for ligands, and has significance for ligand exchange in structure-based drug design. © International Union of Crystallography 2007.

UOW Authors


  •   Blanchard, Helen (external author)

Publication Date


  • 2007

Citation


  • Collins, P. M., Hidari, K. I. P. J., & Blanchard, H. (2007). Slow diffusion of lactose out of galectin-3 crystals monitored by X-ray crystallography: Possible implications for ligand-exchange protocols. Acta Crystallographica Section D: Biological Crystallography, 63(3), 415-419. doi:10.1107/S090744490605270X

Scopus Eid


  • 2-s2.0-33947301415

Start Page


  • 415

End Page


  • 419

Volume


  • 63

Issue


  • 3