id: Pfam:PF14298
pfam_id: PF14298
name: Xenosiderophore-binding lipoprotein XusB
short_name: XusB
seed_status: EX_DUF
characterization_status: UNSCORED
curation_status: SEEDED
source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/PF14298
counters:
  proteins: 1660
  matches: 1673
  proteomes: 872
  taxa: 1301
  structures: 8
  alphafold_models: 1059
  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:IPR025401
description: 'This entry represents XusB, a surface-exposed lipoprotein found exclusively in Bacteroidetes
  that functions in xenosiderophore acquisition. XusB adopts a unique seven-bladed beta-propeller fold
  with a deep, positively charged central calyx that binds enterobactin and other catecholate siderophores
  with high affinity (Kd = 148 nM for enterobactin) [[cite:PUB00162406]]. The protein is enriched in outer
  membrane vesicles (OMVs) and can be secreted into the extracellular milieu. XusB forms part of the xenosiderophore
  utilization system (xus operon: xusABC) in Bacteroides thetaiotaomicron, where it captures siderophores
  produced by other bacteria, particularly during iron-limiting conditions such as intestinal inflammation
  [[cite:PUB00162406],[cite:PUB00162407]]. XusB-bound enterobactin is shielded from sequestration by host
  lipocalin-2, thereby modifying nutritional immunity and potentially benefiting both commensal and pathogenic
  bacteria. The N-terminus contains a lipobox-like sequence with a conserved cysteine (typically at position
  23) that is essential for membrane association, followed by a lipoprotein export signal (LES). Structural
  homologues are encoded by diverse Bacteroidetes species with conserved genetic synteny, though primary
  sequences are poorly conserved. This domain was previously annotated as DUF4374 (domain of unknown function
  4374).'