OmcS cytochrome nanowire

cellstructuremech:omcs_cytochrome_nanowire · Appendage · Appendage · Proposed

An extracellular electrically conductive Geobacter sulfurreducens PCA filament assembled as a helical array of OmcS six-heme c-type cytochrome monomers whose stacked hemes provide a path for long-range electron transport. [DOI:10.1016/j.cell.2019.03.029]

Synonyms: OmcS nanowire; cytochrome-based bacterial 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
OmcS six-heme c-type cytochrome	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	omcS		ESSENTIAL	Six-heme c-type cytochrome subunit that packs head-to-tail into the extracellular conductive nanowire and aligns hemes along the filament axis. `DOI:10.1016/j.cell.2019.03.029` Wang et al. 2019 solved the cryo-EM structure of Geobacter sulfurreducens OmcS nanowires and modeled stacked OmcS monomers as the proteinaceous filament. `DOI:10.1038/s42003-019-0448-9` Filman et al. 2019 independently resolved OmcS as head-to-tail stacked monomers in an extracellular Geobacter sulfurreducens cytochrome filament.

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.

OmcS six-heme c-type cytochrome

Accession	Protein	Gene	Organism	Entry
`UniProtKB:Q74A86`	C-type cytochrome OmcS	omcS	Geobacter sulfurreducens PCA (`NCBITaxon:243231`)	REVIEWED
Role and evidence (2 references) Reviewed UniProtKB entry for the Geobacter sulfurreducens PCA OmcS protein linked to the cryo-EM OmcS nanowire structures PDB:6EF8 and PDB:6NEF. `PDB:6EF8` RCSB PDB entry 6EF8 links its OmcS cryo-EM model to UniProtKB:Q74A86 and the Wang et al. 2019 Cell publication. `PDB:6NEF` RCSB PDB entry 6NEF links its OmcS cryo-EM model to UniProtKB:Q74A86 and the Filman et al. 2019 Communications Biology publication.

Taxonomic distribution

NCBITaxon:243231 Geobacter sulfurreducens PCA — COMMON: Geobacter sulfurreducens PCA is the source strain for the OmcS polymer entity in the PDB:6EF8 cryo-EM model of OmcS nanowires. [PDB:6EF8]

Canonical examples

NCBITaxon:243231 Geobacter sulfurreducens PCA — Strain whose OmcS polymer entity was deposited in the PDB:6NEF cryo-EM model of a helical, cytochrome-based nanowire. [PDB:6NEF]

Functions

stacked-heme long-range electron transfer — OmcS monomers align six covalently bound hemes per subunit into a continuous chain along the filament axis, providing a redox path for long-range electron transfer in purified nanowires.
- DOI:10.1016/j.cell.2019.03.029 Wang et al. 2019 connected the OmcS filament's stacked heme arrangement with micrometer-scale electron transport in purified nanowires.
- DOI:10.1038/s42003-019-0448-9 Filman et al. 2019 resolved a 3.4 A OmcS filament structure whose continuous heme stack can support long-range electron transport.

Mechanism graphs

OmcS monomers align hemes for nanowire conduction (FUNCTION)

OmcS six-heme c-type cytochrome monomers polymerize into a helical extracellular filament in which a stacked heme chain runs along the nanowire axis and provides a path for long-range electron transfer.

Subject	Predicate	Object	Evidence
OmcS six-heme c-type cytochrome	polymerizes into	OmcS cytochrome nanowire	`DOI:10.1038/s42003-019-0448-9` Filman et al. 2019 reconstructed OmcS monomers stacked head-to-tail in a helical bacterial nanowire.
OmcS six-heme c-type cytochrome	aligns	stacked heme chain	`DOI:10.1016/j.cell.2019.03.029` Wang et al. 2019 described the stacked heme arrangement in the OmcS filament cryo-EM structure. `DOI:10.1038/s42003-019-0448-9` Filman et al. 2019 resolved OmcS monomers around an unbranched heme chain in the filament core.
stacked heme chain	supports	long-range extracellular electron transfer	`DOI:10.1016/j.cell.2019.03.029` Wang et al. 2019 linked heme packing to electron transport over micrometer-length OmcS nanowires. `DOI:10.1038/s42003-019-0448-9` Filman et al. 2019 proposed the heme chain as the filament's long-range electron transport path.

Discussions

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

Evidence

DOI:10.1016/j.cell.2019.03.029 Wang, Gu, O'Brien et al. 2019, Structure of Microbial Nanowires Reveals Stacked Hemes that Transport Electrons over Micrometers, Cell.
DOI:10.1038/s42003-019-0448-9 Filman, Marino, Ward et al. 2019, Cryo-EM reveals the structural basis of long-range electron transport in a cytochrome-based bacterial nanowire, Communications Biology.

Curation history

2026-09-11T14:55:39Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-11T14:56:44Z codex · EXPANDED_RECORD — Added OmcS cytochrome nanowire synonymy, GO cell-projection parentage, a label-only OmcS component with a Geobacter sulfurreducens PCA UniProt example, species-level Geobacter sulfurreducens scope and exemplar rows, stacked-heme electron-transfer function evidence, a narrow OmcS function graph, and a TODO for exact OmcS family grounding.
2026-09-11T15:03:41Z codex · ADDRESS_REVIEW — Resolved #504 by narrowing OmcS taxon rows to Geobacter sulfurreducens PCA, and resolved #505 by removing GO cell-projection parentage and cell-projection wording from the definition.

Source: data/structures/appendage/omcs_cytochrome_nanowire.yaml