The Catalytic Redox Machine NioFeoS and FeoFeS Clusters

The Catalytic Redox Machine NioFeoS and FeoFeS Clusters 

The first example of a naturally occuring center containing nickel and iron was in CO dehydrogenase/acetyl-CoA synthase (Ragsdale et al., 1985). Ten years later, it was found that the NiFe hydrogenase also contains a bimetallic NiFe center coordinated to the protein through four cysteinyl 

FIGURE 4. The active site of hydrogenase. a. Structure of the [NiFe] cluster, b. Structure of the H cluster of the Fe-only hydrogenase. From (Nicolet et al., 1999). 

FIGURE 5. Proposed catalytic mechanism of hydrogenase catalysis. See text for description. From (Amara et al., 1999). 

---