UniProtKB - P23837 (PHOQ_ECOLI)
Protein
Sensor protein PhoQ
Gene
phoQ
Organism
Escherichia coli (strain K12)
Status
Functioni
Member of the two-component regulatory system PhoP/PhoQ involved in adaptation to low Mg2+ environments and the control of acid resistance genes. In low periplasmic Mg2+, PhoQ functions as a membrane-associated protein kinase that undergoes autophosphorylation and subsequently transfers the phosphate to PhoP, resulting in the expression of PhoP-activated genes (PAG) and repression of PhoP-repressed genes (PRG). In high periplasmic Mg2+, acts as a protein phosphatase that dephosphorylates phospho-PhoP, resulting in the repression of PAG and may lead to expression of some PRG (By similarity). PhoP-regulated transcription is redox-sensitive, being activated when the periplasm becomes more reducing (deletion of dsbA/dsbB, or treatment with dithiothreitol). MgrB acts between DsbA/DsbB and PhoP/PhoQ in this pathway; the 2 periplasmic Cys residues of MgrB are required for its action on PhoQ, which then acts on PhoP. Mediates magnesium influx to the cytosol by activation of mgtA. Promotes expression of the two-component regulatory system rstA/rstB and transcription of the hemL, mgrB, nagA, slyB, vboR and yrbL genes.By similarity1 Publication
Miscellaneous
There is a close linkage between the PhoP/PhoQ and Rcs signaling systems, and both signaling systems respond to certain external divalent cations (zinc and magnesium).
Two-component regulatory system EvgA/EvgS interacts with PhoP/PhoQ via signal transduction mediated by phospho-EvgA.
Catalytic activityi
- ATP + protein L-histidine = ADP + protein N-phospho-L-histidine. EC:2.7.13.3
Activity regulationi
Acetyl-CoA acts as a non-competitive inhibitor of the PhoQ autokinase activity. Feedback inhibited by MgrB, which seems to bind PhoQ, altering its activity and that of downstream effector PhoP.3 Publications
Kineticsi
- KM=20.93 µM for ATP (at 22 degrees Celsius and pH 8, in the presence of 50 mM KCl and 1 mM MgCl2)2 Publications
- KM=55 µM for ATP (at 22 degrees Celsius and pH 8, in the presence of 25 mM KCl and 0.4 mM MgCl2)2 Publications
Sites
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Metal bindingi | 151 | Divalent metal cation | 1 | |
Metal bindingi | 152 | Divalent metal cation | 1 | |
Sitei | 202 | Plays a critical role in the switching between kinase and phosphatase states | 1 | |
Metal bindingi | 385 | Magnesium | 1 | |
Metal bindingi | 442 | Magnesium | 1 |
Regions
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Nucleotide bindingi | 385 – 393 | ATP | 9 | |
Nucleotide bindingi | 415 – 420 | ATP | 6 | |
Nucleotide bindingi | 434 – 446 | ATPAdd BLAST | 13 |
GO - Molecular functioni
- ATP binding Source: UniProtKB-KW
- identical protein binding Source: IntAct
- kinase activity Source: EcoCyc
- metal ion binding Source: EcoCyc
- phosphoprotein phosphatase activity Source: EcoCyc
- phosphorelay sensor kinase activity Source: EcoCyc
GO - Biological processi
- cellular response to magnesium starvation Source: EcoCyc
- osmosensory signaling via phosphorelay pathway Source: EcoCyc
- phosphorelay signal transduction system Source: GO_Central
- protein autophosphorylation Source: EcoCyc
- signal transduction Source: EcoCyc
Keywordsi
Molecular function | Hydrolase, Kinase, Protein phosphatase, Transferase |
Biological process | Two-component regulatory system |
Ligand | ATP-binding, Magnesium, Metal-binding, Nucleotide-binding |
Enzyme and pathway databases
BioCyci | EcoCyc:PHOQ-MONOMER |
BRENDAi | 2.7.13.3, 2026 |
SABIO-RKi | P23837 |
Names & Taxonomyi
Protein namesi | |
Gene namesi | Name:phoQ Ordered Locus Names:b1129, JW1115 |
Organismi | Escherichia coli (strain K12) |
Taxonomic identifieri | 83333 [NCBI] |
Taxonomic lineagei | Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacterales › Enterobacteriaceae › Escherichia › |
Proteomesi |
|
Subcellular locationi
Plasma membrane
- Cell inner membrane 1 Publication; Multi-pass membrane protein 1 Publication
Plasma Membrane
- integral component of plasma membrane Source: EcoCyc
- plasma membrane Source: EcoCyc
Topology
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Topological domaini | 1 – 16 | CytoplasmicSequence analysisAdd BLAST | 16 | |
Transmembranei | 17 – 37 | HelicalSequence analysisAdd BLAST | 21 | |
Topological domaini | 38 – 194 | PeriplasmicSequence analysisAdd BLAST | 157 | |
Transmembranei | 195 – 215 | HelicalSequence analysisAdd BLAST | 21 | |
Topological domaini | 216 – 486 | CytoplasmicSequence analysisAdd BLAST | 271 |
Keywords - Cellular componenti
Cell inner membrane, Cell membrane, MembranePathology & Biotechi
Mutagenesis
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Mutagenesisi | 27 | V → N: Shows Mg(2+)-dependent signaling and partial gene activation activity; when associated with A-202. 1 Publication | 1 | |
Mutagenesisi | 30 | L → N: Shows Mg(2+)-dependent signaling and displays higher gene activation activity than wild-type; when associated with A-202. 1 Publication | 1 | |
Mutagenesisi | 47 | T → L: No significant effect (with or without MgCl(2) or CaCl(2)). 1 Publication | 1 | |
Mutagenesisi | 48 | T → A, C, E, M, N, Q, S or V: No significant effect (with or without MgCl(2) or CaCl(2)). 1 Publication | 1 | |
Mutagenesisi | 48 | T → D, G, H, I, K, L, P or R: Confers less than 30% of the wild-type levels of PhoP/PhoQ-signaling cascade in absence of CaCl(2) or MgCl(2). 1 Publication | 1 | |
Mutagenesisi | 48 | T → F or W: Decreased sensitivity to repression by calcium but not by magnesium. 1 Publication | 1 | |
Mutagenesisi | 48 | T → Y: Higher activity than wild-type (with or without MgCl(2) or CaCl(2)). 1 Publication | 1 | |
Mutagenesisi | 50 | R → D: Large decrease in the transcriptional activation of PhoQ-dependent genes. 1 Publication | 1 | |
Mutagenesisi | 54 | G → D: Very large decrease in the transcriptional activation of PhoQ-dependent genes. 1 Publication | 1 | |
Mutagenesisi | 68 | N → L: No significant effect (with or without MgCl(2) or CaCl(2)). 1 Publication | 1 | |
Mutagenesisi | 90 | D → A: No significant effect (with or without MgCl(2) or CaCl(2)). 1 Publication | 1 | |
Mutagenesisi | 148 – 154 | EDDDDAE → QNNNNAQ: Unable to bind divalent cations in vitro and impaired in the ability to respond to Mg(2+) deprivation in vivo. 1 Publication | 7 | |
Mutagenesisi | 149 | D → A: Wild-type effect concerning mgrB transcription. 1 Publication | 1 | |
Mutagenesisi | 150 | D → I: Wild-type effect concerning mgrB transcription. 1 Publication | 1 | |
Mutagenesisi | 151 | D → I: Wild-type effect concerning mgrB transcription. 1 Publication | 1 | |
Mutagenesisi | 152 | D → F: Wild-type effect concerning mgrB transcription. 1 Publication | 1 | |
Mutagenesisi | 179 | D → L or A: Locked-on mutant defective in Mg(2+)-sensing and unable to control its phosphorylation state and phosphotransfer to phoP. 2 Publications | 1 | |
Mutagenesisi | 179 | D → R: Very large decrease in the transcriptional activation of PhoQ-dependent genes. 2 Publications | 1 | |
Mutagenesisi | 199 | L → N: Shows Mg(2+)-dependent signaling and partial gene activation activity; when associated with A-202. 1 Publication | 1 | |
Mutagenesisi | 202 | N → A: Is blind to signal, fails to activate transcription of PhoQ-dependent genes, and abrogates transcription when coexpressed with wild-type PhoQ. Shows no detectable autophosphorylation. Still displays phosphatase activity. Recovers Mg(2+)-dependent signaling and partial gene activation activity; when associated with N-27 or N-199 or N-203 or N-205. Recovers Mg(2+)-dependent signaling and displays higher gene activation activity than wild-type; when associated with N-30. 1 Publication | 1 | |
Mutagenesisi | 202 | N → I, L, M, F, W, Y, V, C, G or P: Is blind to signal, fails to activate transcription of PhoQ-dependent genes, and abrogates transcription when coexpressed with wild-type PhoQ. 1 Publication | 1 | |
Mutagenesisi | 202 | N → R, D, Q, E or H: Shows similar activity profile to wild-type. 1 Publication | 1 | |
Mutagenesisi | 203 | L → N: Shows Mg(2+)-dependent signaling and partial gene activation activity; when associated with A-202. 1 Publication | 1 | |
Mutagenesisi | 205 | L → N: Shows Mg(2+)-dependent signaling and partial gene activation activity; when associated with A-202. 1 Publication | 1 | |
Mutagenesisi | 392 | K → A: 44-fold decrease in ATP affinity and 6-fold decrease in activity. 1 Publication | 1 | |
Mutagenesisi | 434 | R → A: 2-fold decrease in ATP affinity and 51-fold decrease in activity. 1 Publication | 1 | |
Mutagenesisi | 439 | R → A: 3-fold decrease in ATP affinity and 2-fold increase in activity. 1 Publication | 1 |
Chemistry databases
DrugBanki | DB04395, Phosphoaminophosphonic Acid-Adenylate Ester |
PTM / Processingi
Molecule processing
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
ChainiPRO_0000074837 | 1 – 486 | Sensor protein PhoQAdd BLAST | 486 |
Amino acid modifications
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Modified residuei | 277 | Phosphohistidine; by autocatalysisPROSITE-ProRule annotation | 1 |
Keywords - PTMi
PhosphoproteinProteomic databases
jPOSTi | P23837 |
PaxDbi | P23837 |
PRIDEi | P23837 |
Expressioni
Inductioni
Interactioni
Subunit structurei
Homodimer; probably dimerizes via the cytoplasmic domain (Probable). Probably interacts with MgrB in the periplasm, altering its activity and that of downstream effector PhoP.
Curated3 PublicationsBinary interactionsi
P23837
With | #Exp. | IntAct |
---|---|---|
itself | 2 | EBI-1113605,EBI-1113605 |
GO - Molecular functioni
- identical protein binding Source: IntAct
Protein-protein interaction databases
BioGRIDi | 4260662, 3 interactors |
DIPi | DIP-10501N |
IntActi | P23837, 2 interactors |
STRINGi | 511145.b1129 |
Structurei
Secondary structure
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details3D structure databases
SMRi | P23837 |
ModBasei | Search... |
PDBe-KBi | Search... |
Miscellaneous databases
EvolutionaryTracei | P23837 |
Family & Domainsi
Domains and Repeats
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Domaini | 215 – 266 | HAMPPROSITE-ProRule annotationAdd BLAST | 52 | |
Domaini | 274 – 480 | Histidine kinasePROSITE-ProRule annotationAdd BLAST | 207 |
Keywords - Domaini
Transmembrane, Transmembrane helixPhylogenomic databases
eggNOGi | COG2205, Bacteria |
HOGENOMi | CLU_000445_42_0_6 |
InParanoidi | P23837 |
PhylomeDBi | P23837 |
Family and domain databases
Gene3Di | 3.30.450.140, 1 hit 3.30.565.10, 1 hit |
InterProi | View protein in InterPro IPR003660, HAMP_dom IPR003594, HATPase_C IPR036890, HATPase_C_sf IPR005467, His_kinase_dom IPR036097, HisK_dim/P_sf IPR015014, PhoQ_Sensor IPR038429, PhoQ_Sensor_sf IPR004358, Sig_transdc_His_kin-like_C |
Pfami | View protein in Pfam PF02518, HATPase_c, 1 hit PF08918, PhoQ_Sensor, 1 hit |
PRINTSi | PR00344, BCTRLSENSOR |
SMARTi | View protein in SMART SM00387, HATPase_c, 1 hit |
SUPFAMi | SSF47384, SSF47384, 1 hit SSF55874, SSF55874, 1 hit |
PROSITEi | View protein in PROSITE PS50885, HAMP, 1 hit PS50109, HIS_KIN, 1 hit |
i Sequence
Sequence statusi: Complete.
P23837-1 [UniParc]FASTAAdd to basket
10 20 30 40 50
MKKLLRLFFP LSLRVRFLLA TAAVVLVLSL AYGMVALIGY SVSFDKTTFR
60 70 80 90 100
LLRGESNLFY TLAKWENNKL HVELPENIDK QSPTMTLIYD ENGQLLWAQR
110 120 130 140 150
DVPWLMKMIQ PDWLKSNGFH EIEADVNDTS LLLSGDHSIQ QQLQEVREDD
160 170 180 190 200
DDAEMTHSVA VNVYPATSRM PKLTIVVVDT IPVELKSSYM VWSWFIYVLS
210 220 230 240 250
ANLLLVIPLL WVAAWWSLRP IEALAKEVRE LEEHNRELLN PATTRELTSL
260 270 280 290 300
VRNLNRLLKS ERERYDKYRT TLTDLTHSLK TPLAVLQSTL RSLRSEKMSV
310 320 330 340 350
SDAEPVMLEQ ISRISQQIGY YLHRASMRGG TLLSRELHPV APLLDNLTSA
360 370 380 390 400
LNKVYQRKGV NISLDISPEI SFVGEQNDFV EVMGNVLDNA CKYCLEFVEI
410 420 430 440 450
SARQTDEHLY IVVEDDGPGI PLSKREVIFD RGQRVDTLRP GQGVGLAVAR
460 470 480
EITEQYEGKI VAGESMLGGA RMEVIFGRQH SAPKDE
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | D90393 Genomic DNA Translation: BAA14391.1 U00096 Genomic DNA Translation: AAC74213.1 AP009048 Genomic DNA Translation: BAA35951.1 M81433 Genomic DNA No translation available. |
PIRi | B41966 |
RefSeqi | NP_415647.1, NC_000913.3 WP_000735412.1, NZ_STEB01000016.1 |
Genome annotation databases
EnsemblBacteriai | AAC74213; AAC74213; b1129 BAA35951; BAA35951; BAA35951 |
GeneIDi | 58461247 946326 |
KEGGi | ecj:JW1115 eco:b1129 |
PATRICi | fig|1411691.4.peg.1137 |
Similar proteinsi
Cross-referencesi
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | D90393 Genomic DNA Translation: BAA14391.1 U00096 Genomic DNA Translation: AAC74213.1 AP009048 Genomic DNA Translation: BAA35951.1 M81433 Genomic DNA No translation available. |
PIRi | B41966 |
RefSeqi | NP_415647.1, NC_000913.3 WP_000735412.1, NZ_STEB01000016.1 |
3D structure databases
Select the link destinations: PDBei RCSB PDBi PDBji Links Updated | PDB entry | Method | Resolution (Å) | Chain | Positions | PDBsum |
1ID0 | X-ray | 1.60 | A | 335-486 | [»] | |
3BQ8 | X-ray | 2.50 | A/B | 43-190 | [»] | |
3BQA | X-ray | 2.00 | A/B | 43-190 | [»] | |
6A8U | X-ray | 1.85 | A/B | 43-190 | [»] | |
6A8V | X-ray | 2.70 | A/B | 43-190 | [»] | |
SMRi | P23837 | |||||
ModBasei | Search... | |||||
PDBe-KBi | Search... |
Protein-protein interaction databases
BioGRIDi | 4260662, 3 interactors |
DIPi | DIP-10501N |
IntActi | P23837, 2 interactors |
STRINGi | 511145.b1129 |
Chemistry databases
DrugBanki | DB04395, Phosphoaminophosphonic Acid-Adenylate Ester |
Proteomic databases
jPOSTi | P23837 |
PaxDbi | P23837 |
PRIDEi | P23837 |
Genome annotation databases
EnsemblBacteriai | AAC74213; AAC74213; b1129 BAA35951; BAA35951; BAA35951 |
GeneIDi | 58461247 946326 |
KEGGi | ecj:JW1115 eco:b1129 |
PATRICi | fig|1411691.4.peg.1137 |
Organism-specific databases
EchoBASEi | EB0725 |
Phylogenomic databases
eggNOGi | COG2205, Bacteria |
HOGENOMi | CLU_000445_42_0_6 |
InParanoidi | P23837 |
PhylomeDBi | P23837 |
Enzyme and pathway databases
BioCyci | EcoCyc:PHOQ-MONOMER |
BRENDAi | 2.7.13.3, 2026 |
SABIO-RKi | P23837 |
Miscellaneous databases
EvolutionaryTracei | P23837 |
PROi | PR:P23837 |
Family and domain databases
Gene3Di | 3.30.450.140, 1 hit 3.30.565.10, 1 hit |
InterProi | View protein in InterPro IPR003660, HAMP_dom IPR003594, HATPase_C IPR036890, HATPase_C_sf IPR005467, His_kinase_dom IPR036097, HisK_dim/P_sf IPR015014, PhoQ_Sensor IPR038429, PhoQ_Sensor_sf IPR004358, Sig_transdc_His_kin-like_C |
Pfami | View protein in Pfam PF02518, HATPase_c, 1 hit PF08918, PhoQ_Sensor, 1 hit |
PRINTSi | PR00344, BCTRLSENSOR |
SMARTi | View protein in SMART SM00387, HATPase_c, 1 hit |
SUPFAMi | SSF47384, SSF47384, 1 hit SSF55874, SSF55874, 1 hit |
PROSITEi | View protein in PROSITE PS50885, HAMP, 1 hit PS50109, HIS_KIN, 1 hit |
ProtoNeti | Search... |
MobiDBi | Search... |
Entry informationi
Entry namei | PHOQ_ECOLI | |
Accessioni | P23837Primary (citable) accession number: P23837 | |
Entry historyi | Integrated into UniProtKB/Swiss-Prot: | November 1, 1991 |
Last sequence update: | November 1, 1991 | |
Last modified: | April 7, 2021 | |
This is version 199 of the entry and version 1 of the sequence. See complete history. | ||
Entry statusi | Reviewed (UniProtKB/Swiss-Prot) | |
Annotation program | Prokaryotic Protein Annotation Program |
Miscellaneousi
Keywords - Technical termi
3D-structure, Direct protein sequencing, Reference proteomeDocuments
- PDB cross-references
Index of Protein Data Bank (PDB) cross-references