P0ABK9 · NRFA_ECOLI
- ProteinCytochrome c-552
- GenenrfA
- StatusUniProtKB reviewed (Swiss-Prot)
- Organism
- Amino acids478 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Catalyzes the reduction of nitrite to ammonia, consuming six electrons in the process (PubMed:11863430, PubMed:18311941, PubMed:20629638, PubMed:9593308).
Has very low activity toward hydroxylamine (PubMed:11863430).
Has even lower activity toward sulfite (PubMed:20629638).
Sulfite reductase activity is maximal at neutral pH (By similarity).
Has very low activity toward hydroxylamine (PubMed:11863430).
Has even lower activity toward sulfite (PubMed:20629638).
Sulfite reductase activity is maximal at neutral pH (By similarity).
Catalytic activity
- 6 Fe(III)-[cytochrome c] + 2 H2O + NH4+ = 6 Fe(II)-[cytochrome c] + 8 H+ + nitrite
Cofactor
Protein has several cofactor binding sites:
Note: Binds 1 Ca2+ ion per monomer.
Note: Binds 5 heme c groups covalently per monomer.
Activity regulation
Subject to competitive inhibition by sulfite.
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
28 μM | nitrite | |||||
30 μM | nitrite | |||||
22 μM | nitrite | |||||
70 μM | sulfite | |||||
30 mM | hydroxylamine |
Pathway
Nitrogen metabolism; nitrate reduction (assimilation).
Features
Showing features for binding site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 94 | Fe (UniProtKB | ChEBI) of heme c 3 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 122 | heme c 1 (UniProtKB | ChEBI); covalent | ||||
Sequence: C | ||||||
Binding site | 125 | heme c 1 (UniProtKB | ChEBI); covalent | ||||
Sequence: C | ||||||
Binding site | 126 | Fe (UniProtKB | ChEBI) of heme c 1 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: K | ||||||
Binding site | 160 | heme c 2 (UniProtKB | ChEBI); covalent | ||||
Sequence: C | ||||||
Binding site | 163 | heme c 2 (UniProtKB | ChEBI); covalent | ||||
Sequence: C | ||||||
Binding site | 164 | Fe (UniProtKB | ChEBI) of heme c 2 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 209 | heme c 3 (UniProtKB | ChEBI); covalent | ||||
Sequence: C | ||||||
Binding site | 212 | heme c 3 (UniProtKB | ChEBI); covalent | ||||
Sequence: C | ||||||
Binding site | 213 | Fe (UniProtKB | ChEBI) of heme c 3 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 215 | Ca2+ (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Binding site | 216 | Ca2+ (UniProtKB | ChEBI) | ||||
Sequence: Y | ||||||
Binding site | 216 | substrate | ||||
Sequence: Y | ||||||
Binding site | 261 | Ca2+ (UniProtKB | ChEBI) | ||||
Sequence: K | ||||||
Binding site | 263 | Ca2+ (UniProtKB | ChEBI) | ||||
Sequence: Q | ||||||
Binding site | 264 | substrate | ||||
Sequence: H | ||||||
Binding site | 275 | Fe (UniProtKB | ChEBI) of heme c 5 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 282 | heme c 4 (UniProtKB | ChEBI); covalent | ||||
Sequence: C | ||||||
Binding site | 285 | heme c 4 (UniProtKB | ChEBI); covalent | ||||
Sequence: C | ||||||
Binding site | 286 | Fe (UniProtKB | ChEBI) of heme c 4 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 301 | Fe (UniProtKB | ChEBI) of heme c 2 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 314 | heme c 5 (UniProtKB | ChEBI); covalent | ||||
Sequence: C | ||||||
Binding site | 317 | heme c 5 (UniProtKB | ChEBI); covalent | ||||
Sequence: C | ||||||
Binding site | 318 | Fe (UniProtKB | ChEBI) of heme c 5 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 393 | Fe (UniProtKB | ChEBI) of heme c 4 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | outer membrane-bounded periplasmic space | |
Molecular Function | calcium ion binding | |
Molecular Function | heme binding | |
Molecular Function | iron ion binding | |
Molecular Function | nitric oxide reductase activity | |
Molecular Function | nitrite reductase (cytochrome, ammonia-forming) activity | |
Biological Process | anaerobic electron transport chain | |
Biological Process | nitrate assimilation |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Protein family/group databases
Names & Taxonomy
Protein names
- Recommended nameCytochrome c-552
- EC number
- Alternative names
Gene names
Organism names
- Organism
- Strains
- Taxonomic lineageBacteria > Pseudomonadota > Gammaproteobacteria > Enterobacterales > Enterobacteriaceae > Escherichia
Accessions
- Primary accessionP0ABK9
- Secondary accessions
Proteomes
Subcellular Location
Phenotypes & Variants
Features
Showing features for mutagenesis.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Mutagenesis | 126 | Almost complete loss of nitrite reductase activity. | ||||
Sequence: K → H, I, or L | ||||||
Mutagenesis | 263 | Increases affinity for nitrite without changing Vmax. | ||||
Sequence: Q → E |
Chemistry
PTM/Processing
Features
Showing features for signal, chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Signal | 1-26 | |||||
Sequence: MTRIKINARRIFSLLIPFFFFTSVHA | ||||||
Chain | PRO_0000006578 | 27-478 | Cytochrome c-552 | |||
Sequence: EQTAAPAKPVTVEAKNETFAPQHPDQYLSWKATSEQSERVDALAEDPRLVILWAGYPFSRDYNKPRGHAFAVTDVRETLRTGAPKNAEDGPLPMACWSCKSPDVARLIQKDGEDGYFHGKWARGGPEIVNNLGCADCHNTASPEFAKGKPELTLSRPYAARAMEAIGKPFEKAGRFDQQSMVCGQCHVEYYFDGKNKAVKFPWDDGMKVENMEQYYDKIAFSDWTNSLSKTPMLKAQHPEYETWTAGIHGKNNVTCIDCHMPKVQNAEGKLYTDHKIGNPFDNFAQTCANCHTQDKAALQKVVAERKQSINDLKIKVEDQLVHAHFEAKAALDAGATEAEMKPIQDDIRHAQWRWDLAIASHGIHMHAPEEGLRMLGTAMDKAADARTKLARLLATKGITHEIQIPDISTKEKAQQAIGLNMEQIKAEKQDFIKTVIPQWEEQARKNGLLSQ |
Proteomic databases
Expression
Induction
Full induction attained in the presence of nitrite. Subject to glucose and nitrate repression.
Structure
Sequence
- Sequence statusComplete
- Sequence processingThe displayed sequence is further processed into a mature form.
- Length478
- Mass (Da)53,703
- Last updated2005-11-08 v1
- ChecksumF965E986412A0456
Mass Spectrometry
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
X72298 EMBL· GenBank· DDBJ | CAA51048.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
U00006 EMBL· GenBank· DDBJ | AAC43164.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
U00096 EMBL· GenBank· DDBJ | AAC77040.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
AP009048 EMBL· GenBank· DDBJ | BAE78072.1 EMBL· GenBank· DDBJ | Genomic DNA |