Investigations of the Efficient Electrocatalytic Interconversions of Carbon Dioxide and Carbon Monoxide by Nickel-Containing Carbon Monoxide Dehydrogenases - The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment - page 72

Figure 1 Four different classes of anaerobic NiFe-containing CODH are classified by the subunit
composition and biological roles. The upper case letters denote the type of metal cluster. The
A-cluster is the active site for acetyl-CoA synthesis. The C-cluster is the active site in which
CO/CO 2 conversion occurs. Several [Fe 4 S 4 ] clusters are required for electron transfers in enzymes
(B-cluster and D-cluster) and Class I and Class II enzymes have two additional [4Fe-4S] clusters
(E and F clusters) in the enzyme complex. Co refers to the cobalt-corrinoid serving as a methyl
carrier.
complex [ 13 ]. In contrast, the role of CODH II Ch remains unclear despite this enzyme
being the most structurally well characterized by X-ray crystallography [ 8 , 14 , 15 ].
The sequence identity and similarity between CODH I Ch and CODH II Ch are 58.3 %
and 73.9 %, respectively. The third member, CODH III Ch, is complexed tightly with
ACS as CODH/ACS, as mentioned above, and catalyzes acetyl-CoA synthesis [ 16 ].