Figure 1.

Representative structures of CODH C-clusters (a) with and (b) without the bridging sulfide. The C-cluster shown in (a) is from the structure of ChCODH (PDB ID 1SU8) and is shown in cyan cartoon with residue numbering following the ChCODH sequence. The bridging sulfide is circled in red. The C-cluster in (b) is from the structure of MtCODH/ACS solved previously (PDB ID 1MJG) and is shown in gray cartoon with residue numbering following the MtCODH/ACS sequence. C-clusters are depicted in ball-and-stick, while ligands are shown as sticks: Ni in green, Fe in orange, S in yellow, and N in blue. Ni and the unique Fe of the C-cluster are labeled Ni and Fe, respectively. All figures were made using PyMOL (60).