id: Pfam:PF01881
pfam_id: PF01881
name: CRISPR associated protein Cas6, C-terminal
short_name: Cas_Cas6_C
seed_status: EX_DUF
characterization_status: UNSCORED
curation_status: SEEDED
source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/PF01881
counters:
  proteins: 1831
  matches: 1832
  proteomes: 1415
  taxa: 2926
  structures: 7
  alphafold_models: 1415
  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:IPR049435
description: 'This group of families is one of several protein families that are always found associated
  with prokaryotic CRISPRs, themselves a family of clustered regularly interspaced short palindromic repeats,
  DNA repeats found in nearly half of all bacterial and archaeal genomes. These DNA repeat regions have
  a remarkably regular structure: unique sequences of constant size, called spacers, sit between each
  pair of repeats [[cite:PUB00020781]]. It has been shown that the CRISPRs are virus-derived sequences
  acquired by the host to enable them to resist viral infection. The Cas proteins from the host use the
  CRISPRs to mediate an antiviral response. After transcription of the CRISPR, a complex of Cas proteins
  termed Cascade cleaves a CRISPR RNA precursor in each repeat and retains the cleavage products containing
  the virus-derived sequence. Assisted by the helicase Cas3, these mature CRISPR RNAs then serve as small
  guide RNAs that enable Cascade to interfere with virus proliferation [[cite:PUB00106643]]. Cas5 contains
  an endonuclease motif, whose inactivation leads to loss of resistance, even in the presence of phage-derived
  spacers [[cite:PUB00109113]]. In Type I and III CRISPR/Cas systems, the Cas6 family of endoribonucleases
  generates functional CRISPR-derived RNAs by site-specific cleavage of repeat sequences in precursor
  transcripts. The structure of Cas6 [[cite:PUB00098896]] showed it adopts a tandem ferredoxin/RRM fold.
  This entry represents the C-terminal domain.'