protocatechuate 3,4-dioxygenase complex

GO:7770085 · Other · Multiprotein complex · Proposed

A protein complex which is capable of protocatechuate 3,4-dioxygenase activity. It consists of an alpha subunit (PcaG) and a beta subunit (PcaH), with the non-heme iron active site formed at the alpha-beta interface. [GO:7770085]

Synonyms: PcaGH complex; PcaHG complex; protocatechuate 3,4-oxygenase complex

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
Protocatechuate 3,4-dioxygenase, alpha subunit	Protein	part of	`InterPro:IPR012786`	pcaG		UNKNOWN	Alpha subunit of the two-component PcaGH intradiol ring-cleavage dioxygenase. `GO:7770085` GO:7770085 defines the protocatechuate 3,4-dioxygenase complex as containing a PcaG alpha subunit. `InterPro:IPR012786` InterPro IPR012786 is the protocatechuate 3,4-dioxygenase alpha subunit family entry. `PMID:25558786` Yamanashi et al. 2015 reconstituted Rhodococcus jostii RHA1 protocatechuate-branch reactions with PcaHG.
Protocatechuate 3,4-dioxygenase, beta subunit	Protein	part of	`InterPro:IPR012785`	pcaH		UNKNOWN	Beta subunit of the PcaGH dioxygenase; the non-heme iron active site is formed at the alpha-beta interface. `GO:7770085` GO:7770085 defines the protocatechuate 3,4-dioxygenase complex as containing a PcaH beta subunit. `InterPro:IPR012785` InterPro IPR012785 is the protocatechuate 3,4-dioxygenase beta subunit family entry. `PMID:25558786` Yamanashi et al. 2015 reconstituted Rhodococcus jostii RHA1 protocatechuate-branch reactions with PcaHG.

Organism-specific protein examples

Named proteins in which each component's role was established, with the organism the evidence comes from. The component above is the taxon-agnostic family; these are the specific entries behind it.

Protocatechuate 3,4-dioxygenase, alpha subunit

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P00436`	Protocatechuate 3,4-dioxygenase alpha chain	pcaG	Pseudomonas putida (`NCBITaxon:303`)	REVIEWED
Role and evidence (2 references) Reviewed Pseudomonas putida pcaG accession for the protocatechuate 3,4-dioxygenase alpha subunit. `UniProtKB:P00436` UniProtKB P00436 is the reviewed Pseudomonas putida entry for pcaG. `PMID:8407791` Frazee et al. 1993 cloned, sequenced and expressed the Pseudomonas putida protocatechuate 3,4-dioxygenase genes.

Protocatechuate 3,4-dioxygenase, beta subunit

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P00437`	Protocatechuate 3,4-dioxygenase beta chain	pcaH	Pseudomonas putida (`NCBITaxon:303`)	REVIEWED
Role and evidence (2 references) Reviewed Pseudomonas putida pcaH accession for the protocatechuate 3,4-dioxygenase beta subunit. `UniProtKB:P00437` UniProtKB P00437 is the reviewed Pseudomonas putida entry for pcaH. `PMID:8407791` Frazee et al. 1993 cloned, sequenced and expressed the Pseudomonas putida protocatechuate 3,4-dioxygenase genes.

Canonical examples

NCBITaxon:101510 Rhodococcus jostii RHA1 — Strain source of the PcaHG protocatechuate-branch in vitro reconstitution cited by GO:7770085. [PMID:25558786]
NCBITaxon:303 Pseudomonas putida — Source of the reviewed PcaG/PcaH protein examples and the pcaG-pcaH gene cloning and expression study. [PMID:8407791]

Functions

protocatechuate 3,4-dioxygenase activity GO:0018578 — The PcaGH complex catalyzes ring cleavage of 3,4-dihydroxybenzoate to 3-carboxy-cis,cis-muconate.
- GO:7770085 GO:7770085 is capable of GO:0018578 protocatechuate 3,4-dioxygenase activity.
- GO:0018578 GO:0018578 is the molecular-function term for protocatechuate 3,4-dioxygenase activity.

Evidence

GO:7770085 Gene Ontology cellular-component term for the protocatechuate 3,4-dioxygenase complex and its PcaGH, PcaHG and protocatechuate 3,4-oxygenase synonymy.
GO:1990204 QuickGO reports GO:7770085 as an is-a child of GO:1990204 oxidoreductase complex.
GO:0018578 Gene Ontology molecular-function term for protocatechuate 3,4-dioxygenase activity.
InterPro:IPR012786 InterPro family entry for protocatechuate 3,4-dioxygenase alpha subunits.
InterPro:IPR012785 InterPro family entry for protocatechuate 3,4-dioxygenase beta subunits.
UniProtKB:P00436 UniProtKB reviewed Pseudomonas putida PcaG entry.
UniProtKB:P00437 UniProtKB reviewed Pseudomonas putida PcaH entry.
PMID:25558786 PubMed identifier for Yamanashi et al. 2015, the Bioscience, Biotechnology, and Biochemistry PcaHG reconstitution paper cited by GO:7770085.
DOI:10.1080/09168451.2014.993915 DOI for Yamanashi et al. 2015, as reported by PubMed.
PMID:8407791 PubMed identifier for Frazee et al. 1993, the Journal of Bacteriology Pseudomonas putida pcaG-pcaH cloning paper cited by UniProtKB P00436 and P00437.
DOI:10.1128/jb.175.19.6194-6202.1993 DOI for Frazee et al. 1993, as reported by UniProtKB.

Curation history

2026-10-02T01:22:14Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-02T01:23:32Z codex · EXPANDED_RECORD — Added PcaGH synonymy, oxidoreductase-complex parentage, exact InterPro-grounded PcaG and PcaH constituents with reviewed Pseudomonas putida UniProt examples, Rhodococcus jostii RHA1 and P. putida canonical examples, protocatechuate 3,4-dioxygenase activity, and GO/PubMed/DOI evidence.

Source: data/structures/other/protocatechuate_3_4_dioxygenase_complex.yaml