id: Pfam:PF03976
pfam_id: PF03976
name: Polyphosphate kinase 2 (PPK2)
short_name: PPK2
seed_status: EX_DUF
characterization_status: UNSCORED
curation_status: SEEDED
source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/PF03976
counters:
  proteins: 18956
  matches: 20776
  proteomes: 12086
  taxa: 16643
  structures: 33
  alphafold_models: 12011
  domain_architectures: 19
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:IPR022488
description: Inorganic polyphosphate (polyP) plays a role in metabolism and regulation and has been proposed
  to serve as a energy source in a pre-ATP world. In prokaryotes, the synthesis and utilisation of polyP
  are catalysed by PPK1, PPK2 and polyphosphatases. Proteins with a single PPK2 domain catalyse polyP-dependent
  phosphorylation of ADP to ATP, whereas proteins containing 2 fused PPK2 domains phosphorylate AMP to
  ADP. The structure of PPK2 from Pseudomonas aeruginosa has revealed a a 3-layer alpha/beta/alpha sandwich
  fold with an alpha-helical lid similar to the structures of microbial thymidylate kinases [[cite:PUB00051190]].