Fig. 18.

Iron-center of GDO from S. pomeroy (PDB: 3BU7) in the N-terminal domain of the bicupin structure. The metal ion is coordinated by the metal binding residues His119, His121 and His160. Outer-shell residues Gln108, His162 and Asp175, which have been suggested to partake in acid–base catalysis are also shown. Note that the metal ion is presumably present in its ferric form in the crystal structure. Oxygen atoms and nitrogen atoms are shown in red and blue, respectively. Water molecules are shown in slate blue. H-bonds are indicated as slate blue dashed lines. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)