id: Pfam:PF24729
pfam_id: PF24729
name: Acb2/Tad1, hairpin domain
short_name: Acb2_Tad1_hairpin
seed_status: EX_DUF
characterization_status: UNSCORED
curation_status: SEEDED
source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/PF24729
counters:
  proteins: 831
  matches: 832
  proteomes: 784
  taxa: 1869
  structures: 20
  alphafold_models: 333
  domain_architectures: 7
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:IPR056098
description: This domain, previously known as DUF7681, is found in phage proteins including Anti-CBASS
  protein 2 (Acb2) and Thoeris anti-defense 1 (Tad1). It folds into an alpha-helical hairpin that is found
  either standalone (in Acb2) or in combination with a four-stranded antiparallel beta-sheet domain (in
  Tad1) [[cite:PUB00153173],[cite:PUB00156031],[cite:PUB00156032]]. Prokaryotic anti-phage immune systems
  use TIR and cGAS-like enzymes to produce 1-3-glycocyclic ADP-ribose; and cyclic dinucleotide and trinucleotide
  signalling molecules, respectively, which limit phage replication. The Thoeris anti-defence proteins
  Tad1 and Tad2 are both pronged inhibitors and antagonise immunity alongside Anti-CBASS protein 2. These
  proteins achieve anti-cyclic-oligonucleotide-based anti-phage signalling system (anti-CBASS) activity
  by sequestering a considerable amount of cyclic nucleotides. Each of these proteins is using distinct
  binding pockets. The residues conserved in Tad1 and Acb2 are located near these binding sites [[cite:PUB00156032],[cite:PUB00156033]].