Nitrogenase_NifE_I: a subgroup of the NifE subunit of the NifEN complex: NifE forms an alpha2beta2 tetramer with NifN. NifE and NifN are structurally homologous to nitrogenase MoFe protein alpha and beta subunits respectively. NifEN participates in the synthesis of the iron-molybdenum cofactor (FeMoco) of the MoFe protein. NifB-co (an iron and sulfur containing precursor of the FeMoco) from NifB is transferred to the NifEN complex where it is further processed to FeMoco. The NifEN bound precursor of FeMoco has been identified as a molybdenum-free, iron- and sulfur- containing analog of FeMoco. It has been suggested that this NifEN bound precursor also acts as a cofactor precursor in nitrogenase systems which require a cofactor other than FeMoco: i.e. iron-vanadium cofactor (FeVco) or iron only cofactor (FeFeco).
Jiyao W et al.(2023). "The conserved domain database in 2023.",