All families / PF09123
PF09123: DUF1931
Domain of unknown function (DUF1931)
- Curation status
- SEEDED
- Seed status
- UNKNOWN CANDIDATE
- Characterization
- UNSCORED
Grounding
PF09123: Domain of unknown function (DUF1931)
IPR015207: integrated entry for Domain of unknown function (DUF1931)
Source description
Members of this family, which are found in a set of hypothetical bacterial proteins, contain a core of six alpha-helices, where one central helix is surrounded by the other five. The exact function of this family has not, as yet, been determined [InterPro reference PUB00035390]. The known structure shows this domain contains two copies of the histone fold [InterPro reference PUB00035390].
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 |
|---|---|---|---|
| O66665 | Uncharacterized protein aq_328 Aquifex aeolicus (strain VF5) | 171 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| O66868 | Uncharacterized protein aq_616 Aquifex aeolicus (strain VF5) | 167 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| Q58904 | Uncharacterized protein MJ1509 Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) | 153 aa; version 1 UniProt 2026_03 | UNIPROT FETCH |
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
- 566
- matches
- 566
- proteomes
- 528
- taxa
- 919
- structures
- 3
- alphafold models
- 412
- domain architectures
- 2
Classification basis
short name matches duf; name says unknown function; domain of unknown function
No scoring reasons supplied.
Related Mech records
| Family | Mech | Record | Protein | Link basis |
|---|---|---|---|---|
| DUF1931 (PF09123) | ProteinTraitsMech | HFD_Aq328-like_rpt1 | Q58904 Uncharacterized protein MJ1509 | canonical example family classification |
| DUF1931 (PF09123) | ProteinTraitsMech | HFD_Aq328-like_rpt2 | Q58904 Uncharacterized protein MJ1509 | canonical example family classification |
| DUF1931 (PF09123) | ProteinTraitsMech | Domain of unknown function (DUF1931) | O66665 Uncharacterized protein aq_328 | canonical example family classification |
| DUF1931 (PF09123) | ProteinTraitsMech | Domain of unknown function (DUF1931) | O66868 Uncharacterized protein aq_616 | canonical example family classification |
| DUF1931 (PF09123) | ProteinTraitsMech | Domain of unknown function (DUF1931) | Q58904 Uncharacterized protein MJ1509 | canonical example family classification |
| DUF1931 (PF09123) | ProteinTraitsMech | Domain of unknown function (DUF1931) | trait identifier |
Curation history and reviews
No retained curation events supplied.
No retained review supplied.
Record source
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.