Active site of AnRut with bound rutin.
(A) Interactions
between hydrophobic (magenta) and aromatic residues (green) in the
+1 subsite of AnRut and docked rutin. The aromatic
side chains of F221, F261, F284, and F286 clamp the aglycone moiety
by π–π stacking interactions shown as yellow dotted
lines.85,87 (B) Superposition of common residues in
the −1 subsites of AnRut (carbon atoms in
green, oxygen in red, and nitrogen in blue) and CaExg (magenta), depicting rutin (green-red) modeled into the active
site of AnRut, and laminaritriose (β-d-Glc-(1 → 3)-β-d-Glc-(1 → 3)-Glc, magenta)
cocrystallized with CaExg (PDBs 3N9K and 1EQC for the ligand and CaExg, respectively). The acid/base catalysts Glu210 and
Glu192 are also shown.