id: Pfam:PF05688
pfam_id: PF05688
name: Bacterial Immunoglobulin-like 21
short_name: BIg21
seed_status: EX_DUF
characterization_status: UNSCORED
curation_status: SEEDED
source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/PF05688
counters:
  proteins: 128
  matches: 334
  proteomes: 72
  taxa: 122
  structures: 1
  alphafold_models: 49
  domain_architectures: 29
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:IPR008542
description: This entry represents BIg21(Bacterial Immunoglobulin-like 21) found in InvasinE (InvE). Invasins
  are members of the inverse autotransporter (IAT) family also referred to as type Ve secretion system.
  In general, they consist of an N-terminal beta-barrel-like domain, which is responsible for attachment
  of invasin to the outer membrane region of bacteria, repetitive Immunoglobuli-like (Ig) domains, which
  vary significantly in number among all the invasins, and the C-terminal domain/adhesion domain (AD)
  [pfam:PF05689], which provides invasins with the specificity to bind to its host target molecules. The
  overall structure of InvE shows that it comprises of three domain architecture in which the domains
  BIg20 (Bacterial Immunoglobulin-like 20) and BIg21 adopt two layer beta-sandwich fold resembling eukaryotic
  members of Immunoglobulin-superfamily (IgSF), while the AD is a globular, alpha/beta-domain. The structure
  of BIg21 belongs to the I2 set of IgSF with a unique modification in the C-E interstrand loop, important
  for its interaction with AD. BIg21 and AD form a functional super-domain as well, necessary to target
  the host receptor [[cite:PUB00101290]].