OmcE cytochrome nanowire

cellstructuremech:omce_cytochrome_nanowire · Appendage · Appendage · Proposed

An extracellular Geobacter sulfurreducens cytochrome nanowire assembled from OmcE tetraheme c-type cytochrome subunits and resolved by cryo-EM as a helical filament whose hemes pack within the filament core. [DOI:10.1038/s41564-022-01159-z]

Synonyms: OmcE cytochrome filament; OmcE nanowire

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
OmcE tetraheme c-type cytochrome	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	omcE		ESSENTIAL	Tetraheme c-type cytochrome subunit that polymerizes into the extracellular OmcE nanowire and packs covalently bound hemes within the filament core. `DOI:10.1038/s41564-022-01159-z` Wang et al. 2022 solved the cryo-EM structure of an extracellular Geobacter OmcE cytochrome filament and modeled OmcE tetraheme cytochrome subunits in the helical assembly. `PDB:7TFS` RCSB PDB entry 7TFS is the helical cryo-EM model of OmcE nanowires from Geobacter sulfurreducens and aligns polymer entity 1 to UniProtKB:Q74FJ0.

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.

OmcE tetraheme c-type cytochrome

Accession	Protein	Gene	Organism	Entry
`UniProtKB:Q74FJ0`	Cytochrome c	omcE	Geobacter sulfurreducens PCA (`NCBITaxon:243231`)	UNREVIEWED
Role and evidence (1 reference) UniProtKB entry for the Geobacter sulfurreducens PCA omcE gene product that aligns to the full polymer entity in the OmcE nanowire cryo-EM structure PDB:7TFS. `PDB:7TFS` RCSB reports a full-length SIFTS alignment from polymer entity 1 of PDB:7TFS to UniProtKB:Q74FJ0.

Taxonomic distribution

NCBITaxon:243231 Geobacter sulfurreducens PCA — COMMON: RCSB reports Geobacter sulfurreducens strain ATCC 51573 / DSM 12127 / PCA as the natural source for the PDB:7TFS OmcE polymer entity. [PDB:7TFS]

Canonical examples

NCBITaxon:243231 Geobacter sulfurreducens PCA — Strain reported by RCSB as the natural source for the OmcE helical cryo-EM model deposited as PDB:7TFS. [PDB:7TFS]

Functions

candidate tetraheme filament electron transfer — OmcE subunits pack four covalently bound hemes per subunit within a helical cytochrome filament, providing a candidate structural path for electron transfer through the nanowire.
- DOI:10.1038/s41564-022-01159-z Wang et al. 2022 reported the tetraheme packing in the extracellular OmcE cytochrome filament and interpreted the heme arrangement as the structural basis for nanowire electron transfer.

Mechanism graphs

OmcE heme packing suggests nanowire conduction (FUNCTION)

OmcE tetraheme c-type cytochromes polymerize into a helical extracellular filament whose packed hemes provide a candidate structural path for electron transfer.

Subject	Predicate	Object	Evidence
OmcE tetraheme c-type cytochrome	polymerizes into	OmcE cytochrome nanowire	`DOI:10.1038/s41564-022-01159-z` Wang et al. 2022 determined the cryo-EM structure of a Geobacter OmcE cytochrome filament assembled from OmcE tetraheme cytochromes.
OmcE tetraheme c-type cytochrome	packs	packed tetraheme core	`DOI:10.1038/s41564-022-01159-z` Wang et al. 2022 resolved tetraheme packing in the OmcE cytochrome filament by cryo-EM.
packed tetraheme core	provides candidate path for	candidate filament electron transfer	`DOI:10.1038/s41564-022-01159-z` Wang et al. 2022 connected the OmcE cytochrome filament's tetraheme packing with its role in electron transfer.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral protein-family grounding for OmcE cytochrome nanowire subunits. The first OmcE cytochrome nanowire record uses an unreviewed Geobacter sulfurreducens PCA UniProtKB example but keeps the component itself label-only because no exact InterPro, Pfam or NCBIfam family CURIE for the extracellular OmcE filament subunit class was verified.

Evidence

DOI:10.1038/s41564-022-01159-z Wang et al. 2022, Cryo-EM structure of an extracellular Geobacter OmcE cytochrome filament reveals tetrahaem packing, Nature Microbiology.
PDB:7TFS RCSB PDB entry 7TFS is a 4.3 A helical cryo-EM model of OmcE nanowires from Geobacter sulfurreducens associated with EMDB map EMD-25879.

Curation history

2026-09-11T15:33:06Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-11T15:33:50Z codex · EXPANDED_RECORD — Added OmcE cytochrome nanowire synonymy, a label-only OmcE component with a Geobacter sulfurreducens PCA UniProt example, Geobacter sulfurreducens PCA taxon rows, cautious electron-transfer function evidence, a narrow OmcE function graph, and a TODO for exact OmcE family grounding.
2026-09-11T15:40:37Z codex · ADDRESS_REVIEW — Resolved #510 by limiting OmcE PCA taxon notes to PDB:7TFS natural source provenance, and resolved #511 by caveating compact OmcE electron-transfer labels and graph terms.

Source: data/structures/appendage/omce_cytochrome_nanowire.yaml