This model represents the majority of known sequences of the nitrogenase molybdenum-iron protein beta subunit. A distinct clade in a phylogenetic tree contains molybdenum-iron, vanadium-iron, and iron-iron forms of nitrogenase beta subunit and is excluded from this model. Nitrogenase, also called dinitrogenase, is responsible for nitrogen fixation. Note: the trusted cutoff score has recently been lowered to include an additional family in which the beta subunit is shorter by about 50 amino acids at the N-terminus. In species with the shorter form of the beta subunit, the alpha subunit has a novel insert of similar length. [Central intermediary metabolism, Nitrogen fixation]
Jiyao W et al.(2023). "The conserved domain database in 2023.",