Docking of (1→3)-β-glucans in the binding cleft of plant 1,3-β-glucanase. The protein, viewed from above the TIM barrel looking into the binding cleft, is shown as a green surface representation, except for the proton donor (118) and nucleophilic (259) residues, which are coloured red, and the subdomain region (magenta). The sugar units of the ligands that are included in the crystallographic model (7G) are shown in orange. The two units of the tetrasaccharide ligand that could not be modelled in electron density because of disorder are tentatively marked in this figure in grey (compare with Fig. 4).