Environment and coordination of FeMo–co in the nitrogenase metallochaperone NafY

In nitrogenase biosynthesis, the iron-molybdenum cofactor (FeMo–co) is externally assembled at scaffold proteins and delivered to the NifDK nitrogenase component by the NafY metallochaperone. Here we have used nuclear magnetic resonance, molecular dynamics, and functional analysis to elucidate the environment and coordination of FeMo–co in NafY. H(121) stands as the key FeMo–co ligand. Regions near FeMo–co diverge from H(121) and include the η1, α1, α2 helical lobe and a narrow path between H(121) and C(196).