Overall structure of 6-P-β-glucosidase and its comparision with 6-P-β-galactosidase. (a) Superposition of the LpPbg1 dimer (grey) and SmBgl (purple and blue). A 6′-P-salicin molecule from the E375Q SmBgl–PSC complex structure is shown in one monomer in ball-and-stick representation. (b, c) Electrostatic surface potential (calculated using APBS; Baker et al., 2001) of LpPbg1 (b) and SmBgl (c). The ligands from the LpPbg1 structure are shown for reference. (d) Superposition of LpPbg1 (green) with apo LpPbg1 chains A (gray) and C (pink). Tryptophan residues from the labile loop are shown as line representations. (e) 6-P-β-Galactosidase in a surface representation (PDB entry 4pbg
). (f–g) Superposition of LpPbg1 (green) with apo LpPbg1 chain A (gray), with either LpPbg1 or apo LpPbg1 shown in a surface representation.