Introducing Se NMR Spectroscopy to Analyzing Galectin -Ligand Interaction.

Their emerging nature as multifunctional effectors explains the large interest to monitor glycan binding to galectins and to define bound-state conformer(s) of their ligands in solution. Basically, NMR spectroscopy facilitates respective experiments. Towards developing new and even better approaches for these purposes, extending the range of exploitable isotopes beyond H, C, and N offers promising perspectives. Having therefore prepared selenodigalactoside and revealed its bioactivity as galectin ligand, monitoring of its binding by Se NMR spectroscopy at a practical level becomes possible by setting up a 2D H, Se CPMG-HSQBMC experiment including CPMG-INEPT long-range transfer. This first step into applying Se as sensor for galectin binding substantiates its potential for screening relative to inhibitory potencies in compound mixtures and for achieving sophisticated epitope mapping. The documented strategic combination of synthetic carbohydrate chemistry and NMR spectroscopy prompts to envision to work with isotopically pure Se-containing β-galactosides and to build on the gained experience with Se by adding F as second sensor in doubly labeled glycosides.