id: Pfam:PF11821
pfam_id: PF11821
name: Alternative complex III, ActD subunit
short_name: ActD
seed_status: EX_DUF
characterization_status: UNSCORED
curation_status: SEEDED
source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/PF11821
counters:
  proteins: 2774
  matches: 2774
  proteomes: 2651
  taxa: 3957
  structures: 8
  alphafold_models: 1860
  domain_architectures: 6
provenance:
  snapshot_id: interpro-pfam-duf-2026-10-10
  path: data/worklists/interpro-pfam-duf-2026-10-10.json
  sha256: 17fb625876c9326ed284263a47bcd84e0d7844a31c040dc06cd2260c36f1c383
  generated_at: '2026-10-10T07:44:21.614711Z'
  source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/
interpro_id: InterPro:IPR021776
description: Alternative complex III (ACIII) is a multisubunit quinol:electron acceptor oxidoreductase
  that couples quinol oxidation with transmembrane proton translocation similar to bc1 complex (or complex
  III). It is a key component of the respiratory and photosynthetic electron transport chains in many
  bacteria. It has six subunits (ActA-F), ActD subunit represented in this entry. The transmembrane regions
  of this subunit form part of the TM arm of the complex [[cite:PUB00099731],[cite:PUB00099732]]. Although
  the function of this subunit is not clear, it may play a role in stabilizing the TM region of ACIII
  which contributes to a stable menaquinol binding pocket and proton translocation passage [[cite:PUB00099732]].