Figure 1.

Overall structure of CN2 and its active site. (A) Overall structure of CN2 in complex with Mn²⁺ (magenta) and bestatin (green) (PDB: 2ZOF) (5). The yellow and blue strands represent individual subunit of a homodimer. Each subunit is composed of one catalytic and one dimerization domains. (B) Structure of the active center of CN2. The bestatin molecule on the active site of one subunit (yellow) is interacted with His 228 of the other subunit (blue) in this crystal through hydrogen bonding (red dashed line). In the active center, there is a dinuclear metal binding site, where one of the metal ligands, D132 (orange), binds to the two metal ions through carboxyl oxygen molecules. Pictures were drawn using PYMOL.26