Formation and insertion of the nitrogenase iron-molybdenum cofactor

The biosynthesis of FeMo-cofactor was described. The metal-sulfur core of FeMo-cofactor was constructed from [4Fe-3S] and [3Fe-Mo-3S] substructures linked by three μ 2-sulfide bridges. The high-resolution crystal structure of the MoFe protein revealed that the central cavity of the FeMo-cofactor contained an interstitial atom. It was also found that the FeMo-cofactor contained homocitrate, an organic constituent, which was attached to the Mo atom through its 2-hydroxy and 2-carboxyl groups.