Fig. 6. Chimeragenesis of SLBR_Hsa and its close homologs.

Dose-response curves of a wild-type GST-SLBR_SK678, b wild-type GST-SLBR_UB10712, and c wild-type GST-SLBR_Hsa to five selected ligands. Dose-response curves of the chimeras d GST-SLBR_SK678^Hsa-loops and e GST-SLBR_UB10712^Hsa-loops which contain the CD, EF, and FG loops of SLBR_Hsa. a–e data points represent the mean value and bars represent the standard deviation. f Quantitation of bound glycans at a concentration of 2 µg/ml to parent and chimeric SLBRs. Individual datapoints are shown in black dots with the bar height and the thin black bars representing the mean and standard deviation. The y axis is the absorbance at 450 nm of each sugar normalized to the absorbance of sTa to each SLBR. Root mean square deviation (rmsd) values were calculated from the normalized average signal of each glycan to compare the similarity of binding profiles between SLBRs. This identifies that both GST-SLBR_SK678^Hsa-loops and GST-SLBR_UB10712^Hsa-loops bind to sTa more strongly than the parent SLBRs. In addition, the chimeric SLBRs now have a preference for glycans more similar to SLBR_Hsa. Specifically, wild-type SLBR_SK678 and _UB10712 bind most strongly to 6S-sLe^X/3’sLn > sLe^X. In contrast, SLBR_Hsa and SLBR_UB10712^Hsa-loops bind sTa > sLe^C > 3’sLn > sLe^X > 6S-sLe^X while SLBR_SK678^Hsa-loops bound sTa > sLe^C/3’sLn > sLe^X/6S-sLe^X. a–f Measurements were performed using 500 nM of immobilized GST-SLBR and the indicated concentrations of each ligand (n = 3 independent experiments performed on protein from a single preparation). Source data are provided as a Source Data file.