All families / PF01934
PF01934: HepT-like
Ribonuclease HepT-like
- Curation status
- SEEDED
- Seed status
- EX DUF
- Characterization
- UNSCORED
Grounding
PF01934: Ribonuclease HepT-like
IPR008201: integrated entry for Ribonuclease HepT-like
Source description
This family includes the toxic component HepT of a type II toxin-antitoxin (TA) system, which has RNase activity. These proteins contain a HEPN (higher eukaryotes and prokaryotes nucleotide-binding) domain and are neutralised through tri-AMPylation by the cognate antitoxin MntA, containing a MNT (minimal nucleotidyltransferase) domain [InterPro reference PUB00097221,InterPro reference PUB00097219,InterPro reference PUB00097220]. HepT-MnA form an heterooctamer (at a 2:6 ratio), a rare organisation for this kind of TA systems. HepT dimerises and enables the formation of a deep cleft at the HEPN-domain interface, containing the RX4-6H motif (where X is any amino acid and the residue immediately after the conserved R is typically a polar amino acid) as the active site that functions as an RNA-cleaving RNase. This type II TA system regulates cell motility and confers plasmid stability [InterPro reference PUB00097219]. Due to the prevalence of these HEPN/MNT modules in bacteria and archaea, it has been suggested that these TA systems may also play a role in the environmental adaptation to extreme habitats [InterPro reference PUB00097220].
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
10 verified sequence examples. FASTA
| UniProt | Protein / organism | Sequence | Provenance |
|---|---|---|---|
| A0A0B0QJR1 | tRNA nuclease HepT Aphanizomenon flos-aquae (strain 2012/KM1/D3) | 147 aa; version 2 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| I3ZRF2 | Probable ribonuclease HepT Thermococcus cleftensis (strain DSM 27260 / KACC 17922 / CL1) | 110 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| O32126 | Putative RNase YutE Bacillus subtilis (strain 168) | 144 aa; version 1 UniProt 2026_03 | PTM REGISTRY MIRROR |
| Q57589 | Putative RNase MJ0125 Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) | 116 aa; version 1 UniProt 2026_03 | UNIPROT FETCH2 sibling references |
| Q57591 | Putative RNase MJ0127 Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) | 121 aa; version 1 UniProt 2026_03 | UNIPROT FETCH2 sibling references |
| Q57876 | Gamma-glutamylcyclotransferase and putative RNase MJ0434 Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) | 222 aa; version 1 UniProt 2026_03 | UNIPROT FETCH2 sibling references |
| Q58613 | Putative RNase MJ1216 Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) | 121 aa; version 1 UniProt 2026_03 | UNIPROT FETCH2 sibling references |
| Q58775 | Putative RNase MJ1380 Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) | 109 aa; version 2 UniProt 2026_03 | UNIPROT FETCH |
| Q58943 | Putative RNase MJ1548 Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) | 87 aa; version 2 UniProt 2026_03 | UNIPROT FETCH |
| Q8ECH6 | mRNA nuclease HepT Shewanella oneidensis (strain ATCC 700550 / JCM 31522 / CIP 106686 / LMG 19005 / NCIMB 14063 / MR-1) | 133 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
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
- 7,949
- matches
- 7,950
- proteomes
- 4,926
- taxa
- 8,359
- structures
- 11
- alphafold models
- 5,432
- domain architectures
- 17
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.
No cross-Mech examples are present in the supplied snapshot.
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.