FIGURE 5.

The three-dimensional structure and ligand binding site of CjAgd31B. A, three-dimensional structure of CjAgd31B as a protein schematic. The N-terminal β-sandwich domain is colored red; the central catalytic (β/α)₈ domain is shown in blue with Inserts 1 and 2 colored purple and pink, respectively; the C-terminal proximal β-sandwich is orange; and the C-terminal distal β-sandwich domain is green. B, observed electron density for the acarbose complex of CjAgd31B (map is at 1 σ in divergent stereo). The nucleophile Asp-412, acid-base Asp-480, and hydrophobic “clamp” residues (discussed in text) are shown. This figure was drawn with CCP4MG (66).