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Protein

Nitrate/nitrite sensor protein NarX

Gene

narX

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: -Experimental evidence at protein leveli

Functioni

Acts as a sensor for nitrate/nitrite and transduces signal of nitrate availability to the NarL protein and of both nitrate/nitrite to the NarP protein. NarX probably activates NarL and NarP by phosphorylation in the presence of nitrate. NarX also plays a negative role in controlling NarL activity, probably through dephosphorylation in the absence of nitrate.

Catalytic activityi

ATP + protein L-histidine = ADP + protein N-phospho-L-histidine.

GO - Molecular functioni

  • ATP binding Source: UniProtKB-KW
  • phosphoprotein phosphatase activity Source: EcoCyc
  • phosphorelay sensor kinase activity Source: EcoCyc
  • protein dimerization activity Source: InterPro

GO - Biological processi

  • cellular response to DNA damage stimulus Source: EcoliWiki
  • cellular response to nitrate Source: EcoCyc
  • cellular response to nitrite Source: EcoCyc
  • nitrate assimilation Source: UniProtKB-KW
  • phosphorelay signal transduction system Source: EcoCyc
  • protein autophosphorylation Source: EcoCyc

Keywordsi

Molecular functionKinase, Transferase
Biological processNitrate assimilation, Two-component regulatory system
LigandATP-binding, Nucleotide-binding

Enzyme and pathway databases

BioCyciEcoCyc:NARX-MONOMER
BRENDAi2.7.13.3 2026

Names & Taxonomyi

Protein namesi
Recommended name:
Nitrate/nitrite sensor protein NarX (EC:2.7.13.3)
Gene namesi
Name:narX
Synonyms:narR
Ordered Locus Names:b1222, JW1213
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG10646 narX

Subcellular locationi

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini1 – 14CytoplasmicSequence analysisAdd BLAST14
Transmembranei15 – 37HelicalSequence analysisAdd BLAST23
Topological domaini38 – 151PeriplasmicSequence analysisAdd BLAST114
Transmembranei152 – 174HelicalSequence analysisAdd BLAST23
Topological domaini175 – 598CytoplasmicSequence analysisAdd BLAST424

GO - Cellular componenti

  • integral component of membrane Source: UniProtKB-KW
  • intracellular Source: GOC
  • plasma membrane Source: EcoCyc

Keywords - Cellular componenti

Cell inner membrane, Cell membrane, Membrane

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000748121 – 598Nitrate/nitrite sensor protein NarXAdd BLAST598

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei399Phosphohistidine; by autocatalysisPROSITE-ProRule annotation1

Keywords - PTMi

Phosphoprotein

Proteomic databases

PaxDbiP0AFA2
PRIDEiP0AFA2

Interactioni

Binary interactionsi

WithEntry#Exp.IntActNotes
narLP0AF282EBI-1112775,EBI-1122899

GO - Molecular functioni

Protein-protein interaction databases

BioGridi4263270, 17 interactors
DIPiDIP-35785N
IntActiP0AFA2, 5 interactors
STRINGi316385.ECDH10B_1281

Structurei

Secondary structure

1598
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Helixi43 – 62Combined sources20
Helixi68 – 70Combined sources3
Helixi71 – 81Combined sources11
Helixi84 – 93Combined sources10
Helixi96 – 108Combined sources13
Helixi110 – 116Combined sources7
Helixi120 – 122Combined sources3
Helixi124 – 150Combined sources27

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
3EZHX-ray1.70A/B38-151[»]
3EZIX-ray1.70A/B/C/D42-148[»]
ProteinModelPortaliP0AFA2
SMRiP0AFA2
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP0AFA2

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini176 – 228HAMPPROSITE-ProRule annotationAdd BLAST53
Domaini393 – 587Histidine kinasePROSITE-ProRule annotationAdd BLAST195

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiENOG4105BZU Bacteria
ENOG410XNMH LUCA
HOGENOMiHOG000275465
InParanoidiP0AFA2
KOiK07673
OMAiNHYGLII
PhylomeDBiP0AFA2

Family and domain databases

CDDicd06225 HAMP, 1 hit
cd00075 HATPase_c, 1 hit
Gene3Di3.30.565.10, 1 hit
InterProiView protein in InterPro
IPR003660 HAMP_dom
IPR003594 HATPase_C
IPR036890 HATPase_C_sf
IPR005467 His_kinase_dom
IPR029095 NarX-like_N
IPR016380 Sig_transdc_His_kin_NarX/NarQ
IPR011712 Sig_transdc_His_kin_sub3_dim/P
PfamiView protein in Pfam
PF00672 HAMP, 1 hit
PF02518 HATPase_c, 1 hit
PF07730 HisKA_3, 1 hit
PF13675 PilJ, 1 hit
PIRSFiPIRSF003167 STHK_NarX/NarQ, 1 hit
SMARTiView protein in SMART
SM00304 HAMP, 1 hit
SM00387 HATPase_c, 1 hit
SUPFAMiSSF55874 SSF55874, 1 hit
PROSITEiView protein in PROSITE
PS50885 HAMP, 1 hit
PS50109 HIS_KIN, 1 hit

Sequencei

Sequence statusi: Complete.

P0AFA2-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MLKRCLSPLT LVNQVALIVL LSTAIGLAGM AVSGWLVQGV QGSAHAINKA
60 70 80 90 100
GSLRMQSYRL LAAVPLSEKD KPLIKEMEQT AFSAELTRAA ERDGQLAQLQ
110 120 130 140 150
GLQDYWRNEL IPALMRAQNR ETVSADVSQF VAGLDQLVSG FDRTTEMRIE
160 170 180 190 200
TVVLVHRVMA VFMALLLVFT IIWLRARLLQ PWRQLLAMAS AVSHRDFTQR
210 220 230 240 250
ANISGRNEMA MLGTALNNMS AELAESYAVL EQRVQEKTAG LEHKNQILSF
260 270 280 290 300
LWQANRRLHS RAPLCERLSP VLNGLQNLTL LRDIELRVYD TDDEENHQEF
310 320 330 340 350
TCQPDMTCDD KGCQLCPRGV LPVGDRGTTL KWRLADSHTQ YGILLATLPQ
360 370 380 390 400
GRHLSHDQQQ LVDTLVEQLT ATLALDRHQE RQQQLIVMEE RATIARELHD
410 420 430 440 450
SIAQSLSCMK MQVSCLQMQG DALPESSREL LSQIRNELNA SWAQLRELLT
460 470 480 490 500
TFRLQLTEPG LRPALEASCE EYSAKFGFPV KLDYQLPPRL VPSHQAIHLL
510 520 530 540 550
QIAREALSNA LKHSQASEVV VTVAQNDNQV KLTVQDNGCG VPENAIRSNH
560 570 580 590
YGMIIMRDRA QSLRGDCRVR RRESGGTEVV VTFIPEKTFT DVQGDTHE
Length:598
Mass (Da):67,084
Last modified:December 20, 2005 - v1
Checksum:i886BA0FC2C8F3C3E
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti42 – 52GSAHAINKAGS → AAPMRSTKRDA (PubMed:2657652).CuratedAdd BLAST11
Sequence conflicti42 – 52GSAHAINKAGS → AAPMRSTKRDA (PubMed:2668029).CuratedAdd BLAST11
Sequence conflicti374A → G in AAA24198 (PubMed:2649492).Curated1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X13360 Genomic DNA Translation: CAA31741.1
U00096 Genomic DNA Translation: AAC74306.1
AP009048 Genomic DNA Translation: BAA36090.1
X15996 Genomic DNA Translation: CAA34125.1
M24910 Genomic DNA Translation: AAA24198.1
X65715 Genomic DNA Translation: CAA46631.1
X69189 Genomic DNA Translation: CAA48934.1
PIRiS26137 RGECNX
RefSeqiNP_415740.1, NC_000913.3
WP_000918073.1, NZ_LN832404.1

Genome annotation databases

EnsemblBacteriaiAAC74306; AAC74306; b1222
BAA36090; BAA36090; BAA36090
GeneIDi945788
KEGGiecj:JW1213
eco:b1222
PATRICifig|1411691.4.peg.1060

Similar proteinsi

Entry informationi

Entry nameiNARX_ECOLI
AccessioniPrimary (citable) accession number: P0AFA2
Secondary accession number(s): P10956
Entry historyiIntegrated into UniProtKB/Swiss-Prot: December 20, 2005
Last sequence update: December 20, 2005
Last modified: March 28, 2018
This is version 106 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome
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Main funding by: National Institutes of Health