Fig. 25.

Active site of (A) Fe(II)-ARD (PDB:1HJI) and (B) Ni(II)-ARD (PDB: 1ZZR). The 6 Å sphere surrounding the metal center of a representative NMR structure from the deposited data-set of NMR structures is shown for each variant. Additionally, for Ni(II)-ARD C-terminal residues in the vicinity of the metal center (Asp157-Ile163) are shown in teal. Note that for the Fe(II)-ARD structure the N-terminus is disordered and hence not present in the deposited structure. Generally, the Ni(II) variant appears more tightly packed around the metal center. Fe(II) is shown in orange, Ni(II) is depicted in green. Oxygen atoms and nitrogen atoms are shown in red and blue, respectively. Metal bound waters have been omitted for clarity. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)