The nitrogenase complex EC:1.18.6.1 catalyses the conversion of molecular nitrogen to ammonia (nitrogen fixation) as follows: 8 reduced ferredoxin + 8 H(+) + N(2) + 16 ATP <=> 8 oxidised ferredoxin + 2 NH(3) + 16 ADP + 16 phosphate. The complex is hexameric, consisting of 2 alpha, 2 beta, and 2 delta subunits. This family represents the delta subunit of a group of nitrogenases that do not utilise molybdenum (Mo) as a cofactor, but instead use either vanadium (V nitrogenases), or iron (alternative nitrogenases). V nitrogenases are encoded by vnf operons, and alternative nitrogenases by anf operons. The delta subunits are VnfG and AnfG, respectively.

1: Culture-independent characterization of a gene responsible for nitrogen fixation in the symbiotic microbial community in the gut of the termite Neotermes koshunensis. Noda S, Ohkuma M, Usami R, Horikoshi K, Kudo T; Appl Environ Microbiol 1999;65:4935-4942. PMID:10543806

2: Activation of vanadium nitrogenase expression in Azotobacter vinelandii DJ54 revertant in the presence of molybdenum. Lei S, Pulakat L, Gavini N; FEBS Lett 2000;482:149-153. PMID:11018539