Spectroscopic Characterization of the Isolated Iron–Molybdenum Cofactor (FeMoco) Precursor from the Protein NifEN

Abstract
The fate of iron eight: The active site of Mo‐nitrogenase is FeMoco. Previously, a FeMoco precursor was captured on NifEN, a scaffold protein for FeMoco biosynthesis. The FeMoco precursor is now isolated from the NifEN. The integrity of the precursor is shown by its full catalytic activity on incorporation into precursor‐deficient NifEN. XAS/EXAFS analysis supports the eight‐iron model of the precursor (see structure: Fe purple, S yellow).