Nitrite reductase (NADH) small subunit (IPR017881)

Short name: NirD

Overlapping homologous superfamilies

Family relationships



In Proteobacteria and Actinobacteria the main nitrite reductase activity is contributed by the NADH-dependent nitrite reductase, which detoxifies the nitrite formed as the product of nitrate reduction. The NADH-nitrite reductase operon consists of 4 genes: nirB, nirD, nirC and cysG. The enzyme is formed by the two subunits nirB and nirD. NirC is a nitrite transporter and cysG is required for the synthesis of sirohaem, a cofactor of the nirB subunit [PMID: 8919448, PMID: 2200672]. NirD displays some sequence similarities with the 2Fe-2S Rieske domain (see PDOC00177), but it does not contain the essential residues for the coordination of the iron sulphur [PMID: 11460929, PMID: 16271700].

The entry includes the NirD subunit.

GO terms

Biological Process

GO:0055114 oxidation-reduction process

Molecular Function

GO:0008942 nitrite reductase [NAD(P)H] activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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