phenylacetyl-CoA 1,2-epoxidase complex

GO:0062077 · Other · Multiprotein complex · Proposed

A PaaA/PaaB/PaaC/PaaE multicomponent monooxygenase complex that catalyzes the NADPH- and oxygen-dependent epoxidation of phenylacetyl-CoA to 2-(1,2-epoxy-1,2-dihydrophenyl)acetyl-CoA. [GO:0062077]

Synonyms: paaABCE 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
1,2-phenylacetyl-CoA epoxidase, subunit A	Protein	part of	`InterPro:IPR011881`	paaA	2 copies in Escherichia coli K-12 Complex Portal CPX-2844	UNKNOWN	Catalytic alpha subunit of the PaaAC hydroxylase core. `GO:0062077` QuickGO annotates E. coli K-12 PaaA as part of the phenylacetyl-CoA 1,2-epoxidase complex. `InterPro:IPR011881` InterPro IPR011881 is the exact 1,2-phenylacetyl-CoA epoxidase subunit A family entry. `PMID:21247899` Grishin et al. 2011 showed that PaaA is necessary for in vitro PA-CoA monooxygenase catalysis and forms the catalytic subunit of the PaaAC hydroxylase core. `ComplexPortal:CPX-2844` Complex Portal CPX-2844 asserts two PaaA copies in the E. coli K-12 PaaABCE phenylacetyl-CoA monooxygenase complex.
1,2-phenylacetyl-CoA epoxidase, subunit B	Protein	part of	`InterPro:IPR009359`	paaB	2 copies in Escherichia coli K-12 Complex Portal CPX-2844	UNKNOWN	Small constituent required for PaaABCE epoxidase catalysis, likely acting as a regulatory or effector subunit. `GO:0062077` QuickGO annotates E. coli K-12 PaaB as part of the phenylacetyl-CoA 1,2-epoxidase complex. `InterPro:IPR009359` InterPro IPR009359 is the 1,2-phenylacetyl-CoA epoxidase subunit B family entry. `PMID:21247899` Grishin et al. 2011 found PaaB necessary for in vitro activity and discussed a possible regulatory role in the PaaABCE complex. `ComplexPortal:CPX-2844` Complex Portal CPX-2844 asserts two PaaB copies in the E. coli K-12 PaaABCE phenylacetyl-CoA monooxygenase complex.
1,2-phenylacetyl-CoA epoxidase, subunit C	Protein	part of	`InterPro:IPR011882`	paaC	2 copies in Escherichia coli K-12 Complex Portal CPX-2844	UNKNOWN	Structural beta subunit of the PaaAC hydroxylase core. `GO:0062077` QuickGO annotates E. coli K-12 PaaC as part of the phenylacetyl-CoA 1,2-epoxidase complex. `InterPro:IPR011882` InterPro IPR011882 is the exact 1,2-phenylacetyl-CoA epoxidase subunit C family entry. `PMID:21247899` Grishin et al. 2011 showed that PaaC is necessary for in vitro PA-CoA monooxygenase catalysis and acts as the structural beta subunit of the PaaAC core. `ComplexPortal:CPX-2844` Complex Portal CPX-2844 asserts two PaaC copies in the E. coli K-12 PaaABCE phenylacetyl-CoA monooxygenase complex.
1,2-phenylacetyl-CoA epoxidase, subunit E	Protein	part of	`InterPro:IPR011884`	paaE	1 copy in Escherichia coli K-12 Complex Portal CPX-2844	UNKNOWN	NADPH/FAD reductase constituent that supplies electrons to the PaaAC hydroxylase core. `GO:0062077` QuickGO annotates E. coli K-12 PaaE as part of the phenylacetyl-CoA 1,2-epoxidase complex. `InterPro:IPR011884` InterPro IPR011884 is the 1,2-phenylacetyl-CoA epoxidase subunit E family entry. `PMID:21247899` Grishin et al. 2011 found PaaE necessary for PaaABCE activity and showed experimentally that PaaE is a reductase. `ComplexPortal:CPX-2844` Complex Portal CPX-2844 asserts one PaaE copy in the E. coli K-12 PaaABCE phenylacetyl-CoA monooxygenase complex.

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.

1,2-phenylacetyl-CoA epoxidase, subunit A

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P76077`	1,2-phenylacetyl-CoA epoxidase, subunit A	paaA	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (2 references) Reviewed E. coli K-12 paaA accession annotated to the phenylacetyl-CoA 1,2-epoxidase complex. `UniProtKB:P76077` UniProtKB P76077 is the reviewed E. coli K-12 entry for 1,2-phenylacetyl-CoA epoxidase subunit A. `PMID:21247899` Grishin et al. 2011 reconstituted activity with E. coli PaaA, PaaB, PaaC and PaaE and solved PaaAC crystal structures.

1,2-phenylacetyl-CoA epoxidase, subunit B

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P76078`	1,2-phenylacetyl-CoA epoxidase, subunit B	paaB	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (2 references) Reviewed E. coli K-12 paaB accession annotated to the phenylacetyl-CoA 1,2-epoxidase complex. `UniProtKB:P76078` UniProtKB P76078 is the reviewed E. coli K-12 entry for 1,2-phenylacetyl-CoA epoxidase subunit B. `PMID:21247899` Grishin et al. 2011 showed that PaaB is one of the subunits necessary for in vitro PaaABCE epoxidase catalysis.

1,2-phenylacetyl-CoA epoxidase, subunit C

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P76079`	1,2-phenylacetyl-CoA epoxidase, subunit C	paaC	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (2 references) Reviewed E. coli K-12 paaC accession annotated to the phenylacetyl-CoA 1,2-epoxidase complex. `UniProtKB:P76079` UniProtKB P76079 is the reviewed E. coli K-12 entry for 1,2-phenylacetyl-CoA epoxidase subunit C. `PMID:21247899` Grishin et al. 2011 showed that PaaC forms the beta subunit of the crystallized PaaAC hydroxylase core.

1,2-phenylacetyl-CoA epoxidase, subunit E

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P76081`	1,2-phenylacetyl-CoA epoxidase, subunit E	paaE	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (2 references) Reviewed E. coli K-12 paaE accession annotated to the phenylacetyl-CoA 1,2-epoxidase complex. `UniProtKB:P76081` UniProtKB P76081 is the reviewed E. coli K-12 entry for 1,2-phenylacetyl-CoA epoxidase subunit E. `PMID:21247899` Grishin et al. 2011 experimentally showed that E. coli PaaE is the PA-CoA oxygenase reductase subunit.

Source composition assertions

paaABCE phenylacetyl-CoA monooxygenase complex (ComplexPortal:CPX-2844)

Escherichia coli (strain K12) (NCBITaxon:83333) · Heterooctamer · ECO:0005547 · retrieved 2026-10-01

Participant	Source type	Source name	Stoichiometry
`CHEBI:49601` — Fe2S2 iron-sulfur cluster	small molecule	fe2s2 iron-sulfur cluster	1
`UniProtKB:P76077` — 1,2-phenylacetyl-CoA epoxidase, subunit A	protein	paaA	2
`UniProtKB:P76078` — 1,2-phenylacetyl-CoA epoxidase, subunit B	protein	paaB	2
`UniProtKB:P76081` — 1,2-phenylacetyl-CoA epoxidase, subunit E	protein	paaE	1
`UniProtKB:P76079` — 1,2-phenylacetyl-CoA epoxidase, subunit C	protein	paaC	2
`CHEBI:24875` — iron cation	small molecule	iron cation	4
`CHEBI:57692` — FAD(3-)	small molecule	fad(3-)	not asserted

Curator-scoped import: E. coli K-12 PaaABCE phenylacetyl-CoA 1,2-epoxidase composition, equivalent to the taxon-specific assembly characterized by Grishin et al. 2011. Source evidence: inferred by curator. The accession was resolved through the Complex Portal accession endpoint; no equivalence xref was inferred.

Canonical examples

NCBITaxon:83333 Escherichia coli K-12 — E. coli K-12 source of the PaaA/PaaB/PaaC/PaaE in vitro reconstitution, PaaAC structural study, UniProtKB examples, and Complex Portal CPX-2844 curation. [PMID:21247899]

Functions

phenylacetyl-CoA 1,2-epoxidase activity GO:0097266 — The PaaABCE complex catalyzes NADPH-dependent epoxidation of phenylacetyl-CoA.
- GO:0062077 GO:0062077 defines the complex by its ability to catalyze phenylacetyl-CoA 1,2-epoxidase activity.
- GO:0097266 GO:0097266 is the molecular-function term for phenylacetyl-CoA 1,2-epoxidase activity.
- PMID:21247899 Grishin et al. 2011 reconstituted the E. coli PaaABCE monooxygenase activity in vitro.

Discussions

INTERPRETATION (RESOLVED): Should PaaD be modeled as a constituent of the phenylacetyl-CoA 1,2-epoxidase complex? No. GO:0062077 uses the paaABCE complex synonym and QuickGO annotates PaaA, PaaB, PaaC and PaaE, but not PaaD, to the complex. Grishin et al. 2011 found that PaaD did not form a stable complex with the other proteins in the tested pull-downs and was not necessary for in vitro PaaABCE catalysis, while noting that it may assist maturation of the monooxygenase in vivo.

Evidence

GO:0062077 Gene Ontology cellular-component term for the phenylacetyl-CoA 1,2-epoxidase complex and its paaABCE complex synonym.
GO:1990204 QuickGO reports GO:0062077 as an is-a descendant of GO:1990204 oxidoreductase complex.
GO:0097266 Gene Ontology molecular-function term for phenylacetyl-CoA 1,2-epoxidase activity.
InterPro:IPR011881 InterPro family entry for PaaA epoxidase subunits.
InterPro:IPR009359 InterPro family entry for PaaB epoxidase subunits.
InterPro:IPR011882 InterPro family entry for PaaC epoxidase subunits.
InterPro:IPR011884 InterPro family entry for PaaE epoxidase subunits.
UniProtKB:P76077 UniProtKB reviewed E. coli K-12 PaaA entry.
UniProtKB:P76078 UniProtKB reviewed E. coli K-12 PaaB entry.
UniProtKB:P76079 UniProtKB reviewed E. coli K-12 PaaC entry.
UniProtKB:P76081 UniProtKB reviewed E. coli K-12 PaaE entry.
PMID:21247899 PubMed identifier for Grishin et al. 2011, the Journal of Biological Chemistry E. coli PaaABCE structural and functional study cited by GO:0062077.
DOI:10.1074/jbc.M110.194423 DOI for Grishin et al. 2011, as reported by PubMed.
ComplexPortal:CPX-2844 Complex Portal entry for the E. coli K-12 PaaABCE phenylacetyl-CoA monooxygenase composition.

Curation history

2026-10-02T02:01:07Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-02T02:02:28Z codex · EXPANDED_RECORD — Added GO synonymy and oxidoreductase-complex parentage, exact InterPro-grounded PaaA/PaaB/PaaC/PaaE constituents with reviewed E. coli K-12 UniProt examples, an E. coli K-12 canonical example, phenylacetyl-CoA 1,2-epoxidase activity, and the PaaD exclusion boundary discussion.
2026-10-02T02:03:15Z complex_portal · ADD_EVIDENCE — Added taxon-specific composition ComplexPortal:CPX-2844 (7 participants); exact accession and taxon verified at import.
2026-10-02T02:04:12Z codex · ADD_EVIDENCE — Added ComplexPortal:CPX-2844 evidence to the PaaA, PaaB, PaaC and PaaE stoichiometry claims and to the record-level evidence list.
2026-10-05T00:17:06Z codex · CORRECTED_METADATA — Issue #2043: preserve 3 nonprotein Complex Portal source name(s) in source_name instead of gene_symbol; identities, labels, taxa, membership and stoichiometry unchanged.

Source: data/structures/other/phenylacetyl_coa_1_2_epoxidase_complex.yaml