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Protein

4-hydroxyphenylacetate 3-monooxygenase oxygenase component

Gene

hpaB

Organism
Escherichia coli
Status
Reviewed-Annotation score: Annotation score: 3 out of 5-Experimental evidence at protein leveli

Functioni

Utilizes FADH2 supplied by HpaC or by another flavin reductase, to catalyze the hydroxylation of 4-hydroxyphenylacetic acid, leading to the production of 3,4-DHPA. Can also oxidize phenol to catechol, and hydroxylate other phenol derivatives.1 Publication

Catalytic activityi

4-hydroxyphenylacetate + FADH2 + O2 = 3,4-dihydroxyphenylacetate + FAD + H2O.1 Publication

Pathwayi: 4-hydroxyphenylacetate degradation

This protein is involved in step 1 of the subpathway that synthesizes pyruvate and succinate semialdehyde from 4-hydroxyphenylacetate.
Proteins known to be involved in the 7 steps of the subpathway in this organism are:
  1. 4-hydroxyphenylacetate 3-monooxygenase oxygenase component (hpaB), 4-hydroxyphenylacetate 3-monooxygenase reductase component (hpaC)
  2. 3,4-dihydroxyphenylacetate 2,3-dioxygenase (hpcB)
  3. 5-carboxymethyl-2-hydroxymuconate semialdehyde dehydrogenase (hpcC)
  4. 5-carboxymethyl-2-hydroxymuconate Delta-isomerase (hpcD), 4-hydroxyphenylacetate degradation bifunctional isomerase/decarboxylase (hpaG), Homoprotocatechuate catabolism bifunctional isomerase/decarboxylase (hpcE)
  5. 4-hydroxyphenylacetate degradation bifunctional isomerase/decarboxylase (hpaG), Homoprotocatechuate catabolism bifunctional isomerase/decarboxylase (hpcE)
  6. 2-oxo-hept-4-ene-1,7-dioate hydratase (hpcG)
  7. 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (hpcH), 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (hpcH), 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (hpaI), 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (yfaU), 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (hpcH), 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (hpcH), 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (hpaI), 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (hpcH), 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (hpaI), 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (hpaI), 4-hydroxy-2-oxo-heptane-1,7-dioate aldolase (hpcH)
This subpathway is part of the pathway 4-hydroxyphenylacetate degradation, which is itself part of Aromatic compound metabolism.
View all proteins of this organism that are known to be involved in the subpathway that synthesizes pyruvate and succinate semialdehyde from 4-hydroxyphenylacetate, the pathway 4-hydroxyphenylacetate degradation and in Aromatic compound metabolism.

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Monooxygenase, Oxidoreductase

Keywords - Biological processi

Aromatic hydrocarbons catabolism

Keywords - Ligandi

FAD, Flavoprotein

Enzyme and pathway databases

BioCyciMetaCyc:MONOMER-2841.
BRENDAi1.14.14.9. 2026.
UniPathwayiUPA00208; UER00416.

Names & Taxonomyi

Protein namesi
Recommended name:
4-hydroxyphenylacetate 3-monooxygenase oxygenase component (EC:1.14.14.9)
Alternative name(s):
4-HPA 3-hydroxylase
4-HPA 3-monooxygenase large component
Gene namesi
Name:hpaB
OrganismiEscherichia coli
Taxonomic identifieri562 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000840321 – 5204-hydroxyphenylacetate 3-monooxygenase oxygenase componentAdd BLAST520

Proteomic databases

PRIDEiQ57160.

Expressioni

Inductioni

By 4-hydroxyphenylacetic acid.

Interactioni

Subunit structurei

4-HPA 3-monooxygenase consists of a reductase component HpaC and an oxygenase component HpaB.

Protein-protein interaction databases

STRINGi469008.ECD_04222.

Family & Domainsi

Sequence similaritiesi

Phylogenomic databases

eggNOGiENOG4105EFA. Bacteria.
COG2368. LUCA.

Family and domain databases

InterProiIPR009075. AcylCo_DH/oxidase_C.
IPR009100. AcylCoA_DH/oxidase_NM_dom.
IPR024677. HpaB/PvcC.
IPR004925. HpaB/PvcC/4-BUDH.
IPR024719. HpaB/PvcC/4-BUDH_C.
IPR024674. HpaB/PvcC/4-BUDH_N.
IPR012688. HpaB_gammaproteobact.
[Graphical view]
PfamiPF03241. HpaB. 1 hit.
PF11794. HpaB_N. 1 hit.
[Graphical view]
PIRSFiPIRSF500125. 4_HPA_large. 1 hit.
PIRSF000331. HpaA_HpaB. 1 hit.
SUPFAMiSSF47203. SSF47203. 1 hit.
SSF56645. SSF56645. 1 hit.
TIGRFAMsiTIGR02310. HpaB-2. 1 hit.

Sequencei

Sequence statusi: Complete.

Q57160-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MKPEDFRAST QRPFTGEEYL KSLQDGREIY IYGERVKDVT THPAFRNAAA
60 70 80 90 100
SVAQLYDALH KPEMQDSLCW NTDTGSGGYT HKFFRVAKSA DDLRHERDAI
110 120 130 140 150
AEWSRLSYGW MGRTPDYKAA FGCALGGTPG FYGQFEQNAR NWYTRIQETG
160 170 180 190 200
LYFNHAIVNP PIDRHLPTDK VKDVYIKLEK ETDAGIIVSG AKVVATNSAL
210 220 230 240 250
THYNMIGFGS AQVMGENPDF ALMFVAPMDA DGVKLISRAS YEMVAGATGS
260 270 280 290 300
PYDYPLSSRF DENDAILVMD NVLIPWENVL LYRDFDRCRR WTMEGGFARM
310 320 330 340 350
YPLQACVRLA VKLDFITALL KKSLECTGTL EFRGVQADLG EVVAWRNTFW
360 370 380 390 400
ALSDSMCSEA TPWVNGAYLP DHAALQTYRV LAPMAYAKIK NIIERNVTSG
410 420 430 440 450
LIYLPSSARD LNNPQIDQYL AKYVRGSNGM DHVQRIKILK LMWDAIGSEF
460 470 480 490 500
GGRHELYEIN YSGSQDEIRL QCLRQAQSSG NMDKMMAMVD RCLSEYDQNG
510 520
WTVPHLHNND DINMLDKLLK
Length:520
Mass (Da):58,848
Last modified:November 1, 1996 - v1
Checksum:i1E93BBCC29BBB55C
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
Z37980 Genomic DNA. Translation: CAA86048.1.
Z29081 Genomic DNA. Translation: CAA82321.1.
PIRiB55349.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
Z37980 Genomic DNA. Translation: CAA86048.1.
Z29081 Genomic DNA. Translation: CAA82321.1.
PIRiB55349.

3D structure databases

ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

STRINGi469008.ECD_04222.

Proteomic databases

PRIDEiQ57160.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Phylogenomic databases

eggNOGiENOG4105EFA. Bacteria.
COG2368. LUCA.

Enzyme and pathway databases

UniPathwayiUPA00208; UER00416.
BioCyciMetaCyc:MONOMER-2841.
BRENDAi1.14.14.9. 2026.

Family and domain databases

InterProiIPR009075. AcylCo_DH/oxidase_C.
IPR009100. AcylCoA_DH/oxidase_NM_dom.
IPR024677. HpaB/PvcC.
IPR004925. HpaB/PvcC/4-BUDH.
IPR024719. HpaB/PvcC/4-BUDH_C.
IPR024674. HpaB/PvcC/4-BUDH_N.
IPR012688. HpaB_gammaproteobact.
[Graphical view]
PfamiPF03241. HpaB. 1 hit.
PF11794. HpaB_N. 1 hit.
[Graphical view]
PIRSFiPIRSF500125. 4_HPA_large. 1 hit.
PIRSF000331. HpaA_HpaB. 1 hit.
SUPFAMiSSF47203. SSF47203. 1 hit.
SSF56645. SSF56645. 1 hit.
TIGRFAMsiTIGR02310. HpaB-2. 1 hit.
ProtoNetiSearch...

Entry informationi

Entry nameiHPAB_ECOLX
AccessioniPrimary (citable) accession number: Q57160
Entry historyi
Integrated into UniProtKB/Swiss-Prot: May 2, 2002
Last sequence update: November 1, 1996
Last modified: November 2, 2016
This is version 77 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Miscellaneous

E.coli K12 lacks the oxygenase component HpaB.

Keywords - Technical termi

Direct protein sequencing

Documents

  1. PATHWAY comments
    Index of metabolic and biosynthesis pathways
  2. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.