Dinitrogenase iron-molybdenum cofactor biosynthesis (IPR003731)

Short name: Di-Nase_FeMo-co_biosynth

Overlapping homologous superfamilies

Domain relationships


This entry represents several Nif (B, X and Y) proteins, which are involved in the biosynthesis of the iron-molybdenum cofactor (FeMo-co) found in the dinitrogenase enzyme of the nitrogenase complex in nitrogen-fixing bacteria. The nitrogenase complex catalyses the reduction of atmospheric dinitrogen to ammonia, and is composed of an iron metalloprotein (dinitrogenase reductase; homodimer of NifH; IPR000392) and a Fe-Mo metalloprotein (dinitrogenase; heterotetramer of NifD and NifK; IPR000318). The pathway for the synthesis of the Fe-Mo cofactor involves several proteins, including NifB, NifE, NifH, NifN, NifQ, NifV and NifX. NifB appears to be an iron-sulphur source for FeMo-co biosynthesis, while NifX may be associated with the mature FeMo-co, in particular with the addition of homocitrate during the last step of biosynthesis [PMID: 11279153]. The NifX protein shows sequence similarity with the C terminus of NifB [PMID: 12892890], as well as to the conserved protein MTH1175 from the archaeon Methanobacterium thermoautotrophicum, which displays a ribonuclease H-like motif of three layers, alpha/beta/alpha, with a single mixed beta-sheet [PMID: 12836677].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.