id: Pfam:PF17541
pfam_id: PF17541
name: Type VI secretion system TssC/VipB, central domain
short_name: TssC
seed_status: EX_DUF
characterization_status: UNSCORED
curation_status: SEEDED
source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/PF17541
counters:
  proteins: 555
  matches: 555
  proteomes: 502
  taxa: 691
  structures: 0
  alphafold_models: 370
  domain_architectures: 4
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:IPR035576
description: This entry represents the central domain of TssC-like proteins. T6SSs are toxin delivery
  systems. It is a multiprotein complex requiring numerous core proteins (Tss proteins) including cytoplasmic,
  transmembrane, and outer membrane components. The needle or tube apparatus is comprised of a phage-like
  complex, similar to the T4 contractile bacteriophage tail, which is thought to be anchored to the membrane
  by a trans-envelope complex [[cite:PUB00090998]]. VipB is a family of Gram-negative type VI secretion
  system components of the tail sheath. They have been known as COG3517. These sheath-components, of which
  there are many copies in the sheath, are also variously referred to as TssC. On contact with another
  bacterial cell the sheath contracts and pushes the puncturing device and tube through the cell envelope
  and punches the target bacterial cell [[cite:PUB00090998]]. VipA and VipB (TssB and TssC) proteins were
  shown to form a cog-wheel like tubular structure in V. cholerae that was noticed to resemble T4 phage
  gp18 polysheath. Two beta-strands of VipA and four beta-strands of VipB intertwine forming the middle
  layer of the sheath. The sheath assembles around an inner Hcp tube and is attached to a structure called
  a baseplate that spans the bacterial membranes. Importantly, VipA/VipB sheath was shown to form a long
  contractile organelle in V. cholerae and in E. coli, suggesting that sheath contraction powers the secretion
  [[cite:PUB00091000]].