alkanesulfonate monooxygenase complex

GO:1990201 · Other · Multiprotein complex · Proposed

A protein complex capable of alkanesulfonate monooxygenase activity. Involved in the utilization of alkanesulfonates as sulfur sources under conditions of sulfate or cysteine starvation, catalyzing the conversion of alkanesulfonates into aldehydes and sulfite. In E.coli the complex consists of a SsuD tetramer. [GO:1990201]

Synonyms: SsuD complex

Part of: GO:0005829 — cytosol (no local record)

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
Alkanesulphonate monooxygenase, FMN-dependent	Protein	part of	`InterPro:IPR019911`	ssuD	4 copies per E. coli SsuD tetramer described by GO:1990201	UNKNOWN	FMNH2-dependent monooxygenase subunit that homotetramerizes to convert alkanesulfonates into aldehydes and sulfite. `GO:1990201` GO:1990201 defines the E. coli alkanesulfonate monooxygenase complex as a SsuD tetramer. `InterPro:IPR019911` InterPro IPR019911 is the FMN-dependent alkanesulphonate monooxygenase family that contains reviewed E. coli K-12 SsuD. `PMID:10480865` Eichhorn et al. 1999 reported SsuD as the E. coli FMNH2-dependent alkanesulfonate monooxygenase in the alkanesulfonate utilization system.

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.

Alkanesulphonate monooxygenase, FMN-dependent

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P80645`	Alkanesulfonate monooxygenase	ssuD	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (2 references) Reviewed E. coli K-12 SsuD accession for the homotetrameric alkanesulfonate monooxygenase represented by GO:1990201. `UniProtKB:P80645` UniProtKB P80645 is the reviewed Escherichia coli K-12 entry for SsuD alkanesulfonate monooxygenase. `PMID:10480865` Eichhorn et al. 1999 characterized E. coli SsuD as the FMNH2-dependent alkanesulfonate monooxygenase.

Canonical examples

NCBITaxon:562 Escherichia coli — E. coli source of the SsuD tetramer described in the GO definition and the GO-cited biochemical characterization paper. [PMID:10480865]

Functions

alkanesulfonate monooxygenase activity GO:0008726 — The SsuD tetramer catalyzes FMNH2-dependent oxygenation of alkanesulfonates into aldehydes and sulfite during sulfur starvation.
- GO:1990201 GO:1990201 is capable of GO:0008726 alkanesulfonate monooxygenase activity.
- GO:0008726 GO:0008726 is the molecular-function term for alkanesulfonate monooxygenase activity.

Physical properties

SUBUNIT_COUNT: 4 (E. coli SsuD tetramer described by GO:1990201) [GO:1990201]

Discussions

INTERPRETATION (RESOLVED): Should the SsuE FMN reductase be modeled as a component of the alkanesulfonate monooxygenase complex? No. GO:1990201 denotes the SsuD tetrameric alkanesulfonate monooxygenase complex, while GO:1990200 separately denotes the SsuD-SsuE complex and GO:1990202 denotes the SsuE FMN reductase dimer.

Evidence

GO:1990201 Gene Ontology cellular-component term for the alkanesulfonate monooxygenase complex and its SsuD complex narrow synonym.
GO:1990204 QuickGO reports GO:1990201 as an is-a child of GO:1990204 oxidoreductase complex.
GO:0005829 — cytosol QuickGO reports GO:1990201 as part of GO:0005829 cytosol.
GO:0008726 Gene Ontology molecular-function term for alkanesulfonate monooxygenase activity.
InterPro:IPR019911 InterPro family entry for FMN-dependent alkanesulphonate monooxygenases.
UniProtKB:P80645 UniProtKB reviewed E. coli K-12 SsuD entry annotated to GO:1990201.
PMID:10480865 PubMed identifier for Eichhorn, van der Ploeg and Leisinger 1999, the Journal of Biological Chemistry SsuD/SsuE characterization paper cited by GO:1990201.
DOI:10.1074/jbc.274.38.26639 DOI for the GO:1990201-cited SsuD/SsuE characterization paper.

Curation history

2026-10-02T00:04:58Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-02T00:06:46Z codex · EXPANDED_RECORD — Added SsuD complex synonymy, oxidoreductase-complex parentage, cytosol parthood, an InterPro-grounded SsuD constituent with an E. coli K-12 reviewed UniProt example, an E. coli canonical example, alkanesulfonate monooxygenase activity, tetrameric subunit count, and a resolved SsuE boundary discussion.

Source: data/structures/other/alkanesulfonate_monooxygenase_complex.yaml