P0A9E5 · FNR_ECOLI
- ProteinFumarate and nitrate reduction regulatory protein
- Genefnr
- StatusUniProtKB reviewed (Swiss-Prot)
- Organism
- Amino acids250 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Global transcription factor that controls the expression of over 100 target genes in response to anoxia. It facilitates the adaptation to anaerobic growth conditions by regulating the expression of gene products that are involved in anaerobic energy metabolism. When the terminal electron acceptor, O2, is no longer available, it represses the synthesis of enzymes involved in aerobic respiration and increases the synthesis of enzymes required for anaerobic respiration.
Miscellaneous
FNR senses the oxygen concentration directly via the disassembly and reassembly of the [4Fe-4S] clusters. Anaerobic, de novo acquisition of the iron-sulfur cluster converts monomeric, inactive apo-FNR into a dimeric form containing two [4Fe-4S] clusters. This, in turn, enhances the affinity of FNR for specific DNA targets and mediates transcription regulation by establishing direct FNR-RNA polymerase contacts. With the increase in intracellular oxygen concentration, the [4Fe-4S] cluster is oxidized, producing a [2Fe-2S] cluster, which decays to apo-FNR. Apo-FNR [4SH] can be reversibly oxidized to a disulfide form [2SH,S-S], suggesting that FNR may be able to sense oxidative stress as well as normoxia. This interconversion may be mediated by agents such as glutathione or thioredoxin.
Cofactor
Note: Binds 1 [4Fe-4S] cluster per subunit.
Features
Showing features for binding site, dna binding.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 20 | [4Fe-4S] cluster (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 23 | [4Fe-4S] cluster (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 29 | [4Fe-4S] cluster (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 122 | [4Fe-4S] cluster (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
DNA binding | 197-216 | H-T-H motif | ||||
Sequence: RGDIGNYLGLTVETISRLLG |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | cytosol | |
Cellular Component | protein-DNA complex | |
Molecular Function | 4 iron, 4 sulfur cluster binding | |
Molecular Function | DNA binding | |
Molecular Function | DNA-binding transcription activator activity | |
Molecular Function | DNA-binding transcription factor activity | |
Molecular Function | iron-sulfur cluster binding | |
Molecular Function | metal ion binding | |
Molecular Function | transcription cis-regulatory region binding | |
Biological Process | anaerobic respiration | |
Biological Process | positive regulation of DNA-templated transcription | |
Biological Process | regulation of DNA-templated transcription | |
Biological Process | response to nitric oxide |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameFumarate and nitrate reduction regulatory protein
Gene names
Organism names
- Organism
- Strains
- Taxonomic lineageBacteria > Pseudomonadota > Gammaproteobacteria > Enterobacterales > Enterobacteriaceae > Escherichia
Accessions
- Primary accessionP0A9E5
- Secondary accessions
Proteomes
Subcellular Location
Phenotypes & Variants
Features
Showing features for mutagenesis.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Mutagenesis | 16 | No effect. | ||||
Sequence: C → A | ||||||
Mutagenesis | 20 | Loss of activity. | ||||
Sequence: C → S | ||||||
Mutagenesis | 22 | Loss of regulation by O2. | ||||
Sequence: D → G | ||||||
Mutagenesis | 23 | Loss of activity. | ||||
Sequence: C → G | ||||||
Mutagenesis | 28 | Loss of regulation by O2. | ||||
Sequence: L → H | ||||||
Mutagenesis | 29 | Loss of activity. | ||||
Sequence: C → G | ||||||
Mutagenesis | 43 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: D → G | ||||||
Mutagenesis | 64 | No effect. | ||||
Sequence: E → Q | ||||||
Mutagenesis | 72 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: R → H | ||||||
Mutagenesis | 73 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: S → F | ||||||
Mutagenesis | 81 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: I → T | ||||||
Mutagenesis | 82 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: T → P | ||||||
Mutagenesis | 85 | Decrease in activity; no effect on DNA-binding. Trace activity; when associated with P-187. | ||||
Sequence: G → A | ||||||
Mutagenesis | 86 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: D → A | ||||||
Mutagenesis | 87 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: E → K | ||||||
Mutagenesis | 88 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: Q → E | ||||||
Mutagenesis | 93 | Loss of regulation by O2. | ||||
Sequence: H → R | ||||||
Mutagenesis | 96 | Loss of activity. | ||||
Sequence: G → D | ||||||
Mutagenesis | 118 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: T → A or P | ||||||
Mutagenesis | 120 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: M → I, R, T, or V | ||||||
Mutagenesis | 122 | Loss of activity. | ||||
Sequence: C → A or S | ||||||
Mutagenesis | 140 | Decrease in activity. | ||||
Sequence: R → A | ||||||
Mutagenesis | 143 | Decrease in activity. | ||||
Sequence: M → A | ||||||
Mutagenesis | 144 | Decrease in activity due to faulty dimerization. | ||||
Sequence: M → A | ||||||
Mutagenesis | 145 | Decrease in activity. | ||||
Sequence: R → A | ||||||
Mutagenesis | 146 | Decrease in activity. | ||||
Sequence: L → A | ||||||
Mutagenesis | 147 | Decrease in activity due to faulty dimerization. | ||||
Sequence: M → A | ||||||
Mutagenesis | 150 | Loss of regulation by O2. | ||||
Sequence: E → K | ||||||
Mutagenesis | 151 | Decrease in activity due to faulty dimerization. | ||||
Sequence: I → A | ||||||
Mutagenesis | 154 | Loss of regulation by O2. | ||||
Sequence: D → A, G, or V | ||||||
Mutagenesis | 158 | Decrease in activity due to faulty dimerization. | ||||
Sequence: I → A | ||||||
Mutagenesis | 181 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: F → L | ||||||
Mutagenesis | 186 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: F → S | ||||||
Mutagenesis | 187 | Decrease in activity; no effect on DNA-binding. Trace activity; when associated with A-85. | ||||
Sequence: S → P | ||||||
Mutagenesis | 191 | Decrease in activity; no effect on DNA-binding. | ||||
Sequence: F → L |
Miscellaneous
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000100161 | 1-250 | Fumarate and nitrate reduction regulatory protein | |||
Sequence: MIPEKRIIRRIQSGGCAIHCQDCSISQLCIPFTLNEHELDQLDNIIERKKPIQKGQTLFKAGDELKSLYAIRSGTIKSYTITEQGDEQITGFHLAGDLVGFDAIGSGHHPSFAQALETSMVCEIPFETLDDLSGKMPNLRQQMMRLMSGEIKGDQDMILLLSKKNAEERLAAFIYNLSRRFAQRGFSPREFRLTMTRGDIGNYLGLTVETISRLLGRFQKSGMLAVKGKYITIENNDALAQLAGHTRNVA |
Proteomic databases
Expression
Gene expression databases
Structure
Family & Domains
Features
Showing features for region, domain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Region | 20-29 | Essential for the oxygen-regulated activity | ||||
Sequence: CQDCSISQLC | ||||||
Region | 47-50 | Activating region 2A | ||||
Sequence: ERKK | ||||||
Region | 60-61 | Activating region 3A | ||||
Sequence: KA | ||||||
Region | 71-75 | Activating region 1A | ||||
Sequence: IRSGT | ||||||
Region | 81 | Activating region 3B | ||||
Sequence: I | ||||||
Region | 85-87 | Activating region 3C | ||||
Sequence: GDE | ||||||
Region | 112 | Activating region 3D | ||||
Sequence: F | ||||||
Region | 116-121 | Activating region 1B | ||||
Sequence: LETSMV | ||||||
Region | 123-124 | Activating region 2B | ||||
Sequence: EI | ||||||
Region | 127-128 | Activating region 2C | ||||
Sequence: ET | ||||||
Region | 140-159 | Dimerization | ||||
Sequence: RQQMMRLMSGEIKGDQDMIL | ||||||
Domain | 164-237 | HTH crp-type | ||||
Sequence: KNAEERLAAFIYNLSRRFAQRGFSPREFRLTMTRGDIGNYLGLTVETISRLLGRFQKSGMLAVKGKYITIENND | ||||||
Region | 181-191 | Activating region 1C | ||||
Sequence: FAQRGFSPREF |
Domain
The amino acid residues contacting the FNR target site on the DNA (5'-TTGATNNNNATCAA-3') are located in the putative DNA-recognition helix (alphaF), which contains the FNR motif (EXXSR). Three surface-exposed loops forming activating region 1 (AR1) in the downstream subunit of the dimer contact the C-terminal domain of the alpha subunit (alphaCTD) of RNA polymerase for activation of class I promoters (the 161-121 loop is the major AR1 activating determinant). At class II promoters, the AR1 of the upstream subunit contacts alphaCTD, promoting open complex formation; activating region 3 (AR3) of the downstream subunit contacts region 4 of the sigma70 subunit of RNA polymerase, to effect direct activation. At promoters repressed by FNR, tandem FNR dimers might interact with each other at AR1 to restrict access to a promoter or jam the promoter by their dual interaction with RNA polymerase alphaCTD.
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Length250
- Mass (Da)27,967
- Last updated2005-07-19 v1
- Checksum33F7BFA2972FF703
Mass Spectrometry
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
J01608 EMBL· GenBank· DDBJ | AAA87981.1 EMBL· GenBank· DDBJ | Genomic DNA | Sequence problems. | |
U00096 EMBL· GenBank· DDBJ | AAC74416.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
AP009048 EMBL· GenBank· DDBJ | BAA14927.1 EMBL· GenBank· DDBJ | Genomic DNA |