Functionally Relevant Interplay between the Fe(4)S(4) Cluster and CN(-) Ligands in the Active Site of [FeFe]-Hydrogenases.
[FeFe]-hydrogenases are highly efficient H(2)-evolving metalloenzymes that include cyanides and carbonyls in the active site. The latter is an Fe(6)S(6) cluster (the so-called H-cluster) that can be subdivided into a binuclear portion carrying the CO and CN(-) groups and a tetranuclear subcluster. The fundamental role of cyanide ligands in increasing the basicity of the H-cluster has been highligh
