PF14130: Cap4_nuclease

Cap4, dsDNA endonuclease domain

Curation status: SEEDED
Seed status: EX DUF
Characterization: UNSCORED

Grounding

PF14130: Cap4, dsDNA endonuclease domain
IPR025382: integrated entry for Cap4, dsDNA endonuclease domain

Source description

This domain family corresponds to the N-terminal of CD-NTase associated protein 4 (Cap4) from bacteria and archaea. CD-NTase-associated protein 4 (Cap4) is a nucleotide second messenger sensor that functions is CBASS immunity. This is the effector domain which has dsDNA nuclease activity, sharing structural homology with type II restriction endonucleases and it has the putative active-site conserved residues required for divalent metal coordination. This domain is inactive as a monomer; after Cap4 signal recognition through its C-terminal SAVED domain (PF18145 (Pfam entry)), it oligomerises to closely locate two nuclease effector domains. This domain does not participates in ligand specificity and it has a promiscuous DNA cleavage response [InterPro reference PUB00094500].

Evidence and references

InterPro entry and its literature references. PUB identifiers are internal InterPro references, not PubMed identifiers. Unresolved citations link to the originating entry.
Frozen description source: InterPro/Pfam API

Source descriptions and links are provenance, not independent functional validation.

Evidence counts: not scored.

Curated functional assertions

No curated functional assertions supplied.

Protein sequence examples

3 verified sequence examples. FASTA

UniProt	Protein / organism	Sequence	Provenance
A0A2K8K5C5	CD-NTase-associated protein 4 Faucicola osloensis	464 aa; version 1 UniProt 2026_03	UNIPROT FETCH 1 sibling references ProteinTraitsMech: Pfam:PF14130
C0VHC9	CD-NTase-associated protein 4 Acinetobacter sp. (strain ATCC 27244 / 9458)	462 aa; version 1 UniProt 2026_03	UNIPROT FETCH 1 sibling references ProteinTraitsMech: Pfam:PF14130
P52127	Anti-bacteriophage protein A Escherichia coli (strain K12)	538 aa; version 1 UniProt 2026_03	UNIPROT FETCH 4 sibling references ProteinTraitsMech: InterPro:IPR014976 ProteinTraitsMech: InterPro:IPR025382 ProteinTraitsMech: Pfam:PF14130 ProteinTraitsMech: Pfam:PF08878

Pfam membership is not functional evidence. Whole-protein sequences do not establish domain boundaries. A coverage gap here is not absence from UniProt.

Sequences and metadata: UniProt Consortium, CC BY 4.0.

Domain matches

No residue-level domain match evidence is available in this build. Structure and AlphaFold counters do not supply coordinates or establish function.

Snapshot counters

proteins: 634
matches: 634
proteomes: 609
taxa: 1,422
structures: 7
alphafold models: 353
domain architectures: 22

Classification basis

pfam previous unknown name

No scoring reasons supplied.

Related Mech records

This family joined the worklist after the frozen cross-Mech scan, so other Mechs were not searched for it. Missing links here are not evidence that other Mechs lack it; rows shown come from mentions of a former DUF/UPF name.

Family	Mech	Record	Protein	Link basis
Cap4_nuclease (PF14130)	TraitMech	Gao-Her-DUF system		record mentions previous pfam name
Cap4_nuclease (PF14130)	TraitMech	Gao-Her system		record mentions previous pfam name

Curation history and reviews

No retained curation events supplied.

No retained review supplied.

Record source

data/families/PF14130.yaml
Family YAML in this build

Download this family (JSON)

Status and evidence

Seed status: A name-based classification of frozen InterPro/Pfam metadata. UNKNOWN CANDIDATE means the metadata explicitly says the function is unknown. KNOWN HISTORICAL DUF means a DUF name matched without that wording; this heuristic is not proof of a known function and does not establish experimental characterization. EX DUF means Pfam renamed the family away from a DUF/UPF name, as recorded in Pfam's previous identifiers; a rename usually follows published work on some members but is naming history, not proof of function for every member. Some EX DUF families' current names or descriptions still say the function is unknown; their classification basis lists this, and scoring does not treat them as characterized. FALSE POSITIVE TEXT HIT means the naming rules did not match.
Characterization: A separate evidence-scoring result. UNSCORED means no score has been calculated; it is not evidence that the family lacks a known function. Missing scores are not negative evidence. PARTIALLY CHARACTERIZED has partial support; KNOWN HISTORICAL DUF can inherit the seed label or reflect a known-function signal. Neither label implies experimental validation.
Evidence counts: Source-specific signals, not unique proteins, publications, or confidence scores. Known counts Rhea reactions and experimentally supported GO molecular-function annotations. Partial counts functional/domain assignments. Context counts structural, environmental, orthology, interaction and neighborhood signals; context alone does not assign function. Repeated annotations may not be independent.
Curation status: Reported separately from seed classification and characterization. SNAPSHOT ONLY means no curated metadata was supplied for this build. SEEDED denotes a source-derived record, not an expert-reviewed functional claim.
Missing counts: Not available means the source did not supply that counter. A zero is a reported count. Not scored means evidence counts are unavailable.