id: Pfam:PF03235
pfam_id: PF03235
name: GmrSD restriction endonuclease, N-terminal domain
short_name: GmrSD_N
seed_status: EX_DUF
characterization_status: UNSCORED
curation_status: SEEDED
source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/PF03235
counters:
  proteins: 14123
  matches: 14176
  proteomes: 8899
  taxa: 14565
  structures: 8
  alphafold_models: 9036
  domain_architectures: 93
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:IPR004919
description: This entry (previously known as DUF262) represents a domain found N-terminal in the GmrSD
  family of modification-dependent restriction endonuclease, including BrxU and SspE proteins [[cite:PUB00155271],[cite:PUB00155272]].
  BrxU is a type IV DNA modification-dependent restriction enzyme, which is promiscuous and uses a range
  of nucleotide and metal co-factors to recognise and cleave DNA that contains any of at least three different
  modifications, and this activity is dependent on the initial nucleotide-driven dissociation of BrxU
  dimers, and subsequent nucleotide hydrolysis [[cite:PUB00155271]]. SspE is a dual-function protein that
  exerts both N-terminal NTPase and C-terminal DNA nicking nuclease activities to defend against phage
  infection [[cite:PUB00155272]]. BrxU targets and cleaves DNA containing one of at least three DNA modifications,
  5mC, 5hmC or glc-5hmC whereas SspE has a phosphorothioate (PT) modification-binding preference and utilizes
  epigenetic PT modification to accomplish self-nonself discrimination and to coordinate its NTPase and
  DNA nicking activities to fight against phages. The domain represented in this entry is involved in
  nucleotide binding, recognition and hydrolysis.