Nitrogenase ligation

Despite the obvious relevance of dinitrogen complexes to the chemistry of the molybdenum-sulfur site of nitrogenase,6 dinitrogen complexes of molybdenum with sulfur ligation have proved to be very elusive. They are confined to the compounds... 

As discussed below, the consensus view of the redox centers present in MoFe proteins is that there are two types (see Ref. 28 for discussion). There are two FeMoco centers (which have the approximate composition one Mo, six to eight Fe, four to nine S, and one homocitrate this is unique to nitrogenase and different from the Mo cofactors of other Mo-containing enzymes), and four [4Fe-4S] centers (the P clusters). If these assignments are correct, then because only 16 Cys residues are invariant among MoFe proteins, conventional Cys ligation to the P ... 

III) the P-clusters of nitrogenase, which may represent a variation of the [4 Fe—4 S] basic structure using different oxidation states and/or different ligation 6 F88) ... 

S-adenosylmethionine (SAM or AdoMet) superfamily, aconitase, and others), enzymes that contain Fe-S heteroatomic clusters (nitrogenase iron-molybdenum cofactor (FeMoco), carbon monoxide dehydrogenase (CODH), and acetyl CoA synthase (ACS)), and enzymes that contain unique ligation sets around specialized iron centers ([NiFe] and [FeFe] hydrogenases) (Figure 1). ... 

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