fig2

Figure 2. Stereoviews of the active site of BiBga42A. (A) E160A/E318A-Gal (cyan) and bound α-Gal (yellow) is superimposed with WT-GOL (white, thin sticks except for glycerol). W200 and F221 are from the neighboring molecule (light purple); (B) and (C) E318S-LNT (green) and bound LNT (yellow) focused on LNB (Galβ1-3GlcNAc) disaccharide structure bound in subsites -1 and +1 (B) and Lac (Galβ1-4Glc) disaccharide structure in subsites +2 and +3 (C). In (B), E160A/E318A-Gal (cyan) and the side chain of Glu-318 in WT-GOL (white) are superimposed as thin sticks. W200 and F221 are from the neighboring molecule (dark green). BiBga42A: a glycoside hydrolase family 42 β-galactosidase; LNT: lacto-N-tetraose; WT-GOL: WT enzyme complexed with glycerol.