Nitrite reductase

Nitrite reductase (NIR) catalyzes the reduction of NO2 to NO. There are 2 classes of NIR: (1) A heme-containing cytochrome Cd type NIR. This enzyme contains 4 heme groups. Its d-type heme group binds NO2. (2) A copper-containing NIR which produces NO2. Under anaerobic conditions bacteria rely on the reduction of nitrogen oxide species to obtain energy. NIR is part of the nitrogen cycle used fot this purpose.

3D structures of nitric reductase3D structures of nitric reductase

Cu-containing nitrite reductase with copper only

1nia, 1nib, 1nic, 1nid, 1nie, 1nif, 2nrd, 1kcb, 1rzp, 1rzq, 2bw4, 2bw5, 2avf – AcNIR + Cu – Achromobacter cycloclastes
2afn, 1aq8, 1as7, 2fjs, 2pp7, 2pp8, 3h4h, 3h56 - AfNIR + Cu – Alcaligenes faecalis
1ntd, 1npj, 1npn, 1zdq, 3h4f - AfNIR (mutant) + Cu
1ndr, 1ndt, 1bq5, 1hau, 1haw, 1oe1, 1oe3 - AxNIR + Cu – Achromobacter xylosoxidans
1oe2, 2jfc - AxNIR (mutant) + Cu
1mzz, 2dy2 - RsNIR + Cu – Rhodobacter sphaeroides
2dv6 - NIR + Cu – Hyphomicrobium denitrificans

Cu-containing nitrite reductase with variety of metals

1et5, 1et8 - AfNIR (mutant) + Zn + Cu
1et7 - AfNIR (mutant) + Cd + Cu
2vm3, 2vm4, 2vw4, 2vw6, 2vw7, 2vn3 - AxNIR + Zn + Cu
2bo0 - AxNIR (mutant) + Zn
2vmj - AxNIR + Zn
1gs6 - AxNIR (mutant) + Mg + Cu
1gs7, 1wae, 1wa0, 1wa1, 2bp0, 2bp8, 2xx0, 2xxf, 2xxg - AxNIR (mutant) + Zn + Cu
2zon - AxNIR + heme + Cu
1mzy, 1zv2, 2a3t - RsNIR + Mg + Cu
1n70 - RsNIR (mutant) + Mg + Cu

Cu-containing nitrite reductase binary complex

1as6, 1as8, 1sjm, 2ppc - AfNIR + NO2 + Cu
2e86 - AfNIR + N3 + Cu
1j9q, 1j9r, 1j9s, 1j9t, 1l9o, 1l9p, 1l9q, 1l9r, 1l9s, 1l9t - AfNIR (mutant) + NO2 + Cu
1zds, 2b08 - AfNIR (mutant) + acetamide + Cu
1snr - AfNIR + NO + Cu
2pp9 - AfNIR + NO3 + Cu
2ppa - AfNIR + N2O + Cu
2ppd, 2ppe, 2ppf - AfNIR (mutant) + NO + Cu
2p80 - AfNIR + pseudoazurin + Cu
1nds - AxNIR + NO2 + Cu
2xx1 - AxNIR (mutant) + NO2 + Cu
2xwz - AxNIR + NO + NO2 + Cu
1wa2 - AxNIR (mutant) + NO2 + Zn + Cu
2bwd, 2bwi - AcNIR + NO2 + Cu
2y1a - AcNIR + NO + Cu
2dws, 2dwt - RsNIR + NO2 + Cu

Heme-containing nitrite reductase

1aof, 1qks, 1hj4, 1hj5, 1h9x, 1hcm - PpNIR – Paracoccus pantotrophus
1gq1 - PpNIR (mutant)
1nir, 1bl9, 1n15, 1n50, 1n90 – PaNIR – Pseudomonas aeruginosa
1hzu - PaNIR (mutant)
1qdb - NIR – Sulfurospirillum deleyianum
1fs7, 1fs8 - WsNIR – Wolinella succinogenes
3bng - WsNIR (mutant)
1gu6, 2rdz, 3tor – EcNIR – Escherichia coli
2rf7 - EcNIR (mutant)
2jo6 – EcNIR small subunit – NMR
2jza - NIR small subunit – Pectobacterium atrosepticum - NMR
1oah – NIR – Desulfovibrio desulfuricans
2j7a - DvNIR – Desulfovibrio vulgaris
2ot4, 3gm6, 3fo3, 3sce, 3uu9 - TnNIR – Thioalkalivibrio nitratireducens

Heme-containing nitrite reductase binary complex

1dy7 - PpNIR + CO
1hj3 - PpNIR + O2
2e81 - WsNIR + NH2OH
2vr0 - DvNIR + HQNO inhibitor

Heme-containing nitrite reductase binary complex with cyanide

1h9y - PpNIR + CN
1gjq - PaNIR + CN
1e2r - NIR + CN – Paracoccus denitrificans

Heme-containing nitrite reductase binary complex with nitric oxide

1nno - PaNIR + NO
1hzv - PaNIR (mutant) + NO
1aom, 1aoq - PpNIR + NO + NO2

Heme-containing nitrite reductase binary complex with nitrite

2e80 - WsNIR + NO2
3bnh - WsNIR (mutant) + NO
3d1i, 3rkh, 3owm - TnNIR + NO2

Heme-containing nitrite reductase binary complex with azide

2zo5 - TnNIR + N3
3s7w - TnNIR + NO2 + N3
1fs9 - WsNIR + N3

Heme-containing nitrite reductase binary complex with sulfite

3mmo - WsNIR + SO3
3bnj - WsNIR (mutant) + SO3
3lg1, 3lgq, 3f29, 3ttb - TnNIR + SO3
3l1t - EcNIR + SO3

Siroheme-containing nitrite reductase

2akj - NIR – spinach
3b0g, 3b0h - ToNIR – tobacco
3b0j, 3b0l, 3b0m, 3b0n - ToNIR (mutant)