Fig. 8. Binding selectivity of FG loop variants in SLBR_SK678, SLBR_UB10713, and SLBR_Hsa.

Dose response curves of biotin-glycan binding to immobilized variant SLBRs (500 nM). Both a the GST-SLBR_SK678^Q367D variant and b the GST-SLBR_UB10712^Q345D variant have substantially reduced binding to the fucosylated ligands sLe^X and 6S-sLe^X. In SLBR_Hsa, charge reversal or neutralization at this same position was assessed in c GST-SLBR_Hsa^D356R and d GST-SLBR_Hsa^D356Q. Both variants had increased binding to 6S-sLe^X, 3’sLn, and sLe^X and decreased binding to sTa, albeit to somewhat different extents. Measurements were performed using 500 nM of immobilized GST-SLBR and the indicated concentrations of each ligand are shown as the mean ± SD (n = 3 independent experiments with a single protein preparation). Statistical comparisons of ligand affinity between FG mutants and parent SLBR can be found in Supplementary Fig. 18. Source data are provided as a Source Data file.