methane-oxidizing organelle

GO:0044227 · Membrane organelle · Membrane bounded organelle · Proposed

A cytoplasmic, membrane-bounded organelle in aerobic methanotrophic bacteria, built from intracytoplasmic membranes that house particulate methane monooxygenase and associated electron-transfer proteins for methane catabolism. [GO:0044227]

Synonyms: methane-oxidizing compartment; methanotroph intracytoplasmic membrane-bound compartment

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
methanotroph intracytoplasmic membrane bilayer	Lipid	part of				ESSENTIAL	Inner-membrane-derived lipid bilayer that expands into the intracytoplasmic membrane network housing pMMO trimers. `DOI:10.1038/s41467-022-32752-9` Zhu et al. 2022 used cryoFIB/SEM volume imaging and cellular cryoET in Methylococcus capsulatus Bath to show that copper-induced ICMs derive from the inner cell membrane and contain embedded pMMO arrays. `DOI:10.1111/1751-7915.13458` Whiddon et al. 2019 developed live-cell fluorescence staining for type I methanotroph ICMs and treated the FM dye signal as labelling highly compressed membrane stacks.
particulate methane monooxygenase complex	Protein complex	part of	Reviewed label only (reviewed name; no accession asserted)	pmoA, pmoB, pmoC		UNKNOWN	Copper membrane monooxygenase trimer embedded in the ICM that oxidizes methane to methanol and packs into native hexagonal arrays. `DOI:10.1038/s41467-022-32752-9` Zhu et al. 2022 resolved native ICM-embedded pMMO trimers and higher-order hexagonal pMMO arrays by cryoET and subtomogram averaging. `DOI:10.1128/JB.183.5.1810-1812.2001` Stolyar et al. 2001 assayed expression of individual Methylococcus capsulatus Bath pmo gene copies encoding particulate methane monooxygenase subunits.

Taxonomic distribution

NCBITaxon:2 Bacteria — RARE: Methane-oxidizing organelles occur in the subset of methanotrophic bacteria that build pMMO-containing intracytoplasmic membranes. [DOI:10.1111/1751-7915.13458]

Canonical examples

NCBITaxon:243233 Methylococcus capsulatus str. Bath — Zhu et al. imaged native ICMs and ICM-embedded pMMO arrays in copper-replete Methylococcus capsulatus Bath cells. [DOI:10.1038/s41467-022-32752-9]

Functions

methane catabolic process GO:0046188 — ICM-localized pMMO oxidizes methane to methanol as the first step in aerobic bacterial methane catabolism.
- DOI:10.1038/s41467-022-32752-9 Zhu et al. 2022 studied pMMO in native ICMs and described methane C-H bond activation and oxidation to methanol as the pMMO reaction.

Mechanism graphs

ICM-embedded pMMO trimers oxidize methane in ordered arrays (FUNCTION)

Methanotroph intracytoplasmic membranes derive from the inner cell membrane, house pMMO trimers, and organize them into native hexagonal arrays. pMMO carries out the membrane-bound oxidation of methane to methanol that starts methane catabolism.

Subject	Predicate	Object	Evidence
methanotroph intracytoplasmic membrane bilayer	bounds	methane-oxidizing organelle	`DOI:10.1038/s41467-022-32752-9` Zhu et al. 2022 visualized Methylococcus capsulatus Bath cells by serial cryoFIB/SEM and cryoET and interpreted ICMs as cytoplasmic-membrane invaginations.
methanotroph intracytoplasmic membrane bilayer	houses	particulate methane monooxygenase complex	`DOI:10.1038/s41467-022-32752-9` Zhu et al. 2022 resolved pMMO trimers within isolated native ICMs and imaged pMMO particle arrays in intact-cell lamellae.
particulate methane monooxygenase complex	forms	hexagonal pMMO array	`DOI:10.1038/s41467-022-32752-9` Zhu et al. 2022 showed by cellular and isolated ICM cryoET that pMMO trimers are arranged in hexagonal arrays.
hexagonal pMMO array	is located in	methane-oxidizing organelle	`DOI:10.1038/s41467-022-32752-9` Zhu et al. 2022 detected pMMO hexagonal arrays covering the ICM surface in intact methanotroph cells.
particulate methane monooxygenase complex	oxidizes	methane	`DOI:10.1038/s41467-022-32752-9` Zhu et al. 2022 describe pMMO as the membrane-bound MMO that catalyzes methane C-H bond activation and oxidation to methanol.
particulate methane monooxygenase complex	produces	methanol	`DOI:10.1038/s41467-022-32752-9` Zhu et al. 2022 state that methane monooxygenases oxidize methane to methanol in methanotrophs.
particulate methane monooxygenase complex	initiates	methane catabolic process	`DOI:10.1038/s41467-022-32752-9` Zhu et al. 2022 identify pMMO as the primary membrane enzyme for methane oxidation in copper-replete methanotrophs.

Evidence

DOI:10.1038/s41467-022-32752-9 Zhu et al. 2022, Structure and activity of particulate methane monooxygenase arrays in methanotrophs, Nature Communications.
DOI:10.1111/1751-7915.13458 Whiddon et al. 2019, Fluorescence-based analysis of the intracytoplasmic membranes of type I methanotrophs, Microbial Biotechnology.
DOI:10.1128/JB.183.5.1810-1812.2001 Stolyar et al. 2001, Expression of individual copies of Methylococcus capsulatus Bath particulate methane monooxygenase genes, Journal of Bacteriology.

Curation history

2026-09-06T08:39:10Z claude · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-06T08:42:35Z claude · EXPANDED_RECORD — Added methane-oxidizing organelle synonyms, GO parent, ICM and pMMO components, taxonomic scope, Methylococcus Bath example, functions, record evidence, and a pMMO-array methane-oxidation graph.
2026-09-06T09:46:24Z claude · FIXED_FUNCTION_SCOPE — Removed native pMMO array organization from functions; retained array packing as a source-backed pMMO component and causal-graph structure.

Source: data/structures/membrane_organelle/methane_oxidizing_organelle.yaml