All families / PF09369
PF09369: MZB
MrfA Zn-binding domain
- Curation status
- SEEDED
- Seed status
- EX DUF
- Characterization
- UNSCORED
Grounding
PF09369: MrfA Zn-binding domain
IPR018973: integrated entry for MrfA Zn-binding domain
Source description
This is the C-terminal MrfA Zn+2-binding domain (MZB, also referred to as DUF1998) which contains a conserved four-cysteine signature motif. These four Cys reside in a short coil between two alpha-helices and form a metal ion-binding site [InterPro reference PUB00098193]. This domain is frequently found at the C-terminal of ndNTPases, however, it is also found encoded in a standalone gene, downstream of putative helicase domain-encoding genes associated with bacterial anti-phage defense system DISARM. MrfA (Mitomycin repair factor A, also known as YprA in Bacillus subtilis) is a DNA helicase that supports repair of mitomycin C-induced DNA damage. MrfA homologues are widely distributed in bacteria and are also present in archaea, fungi and plants. The MrfA-homologue in yeast, Hrq1, also reduces mitomycin C sensitivity. Hrq1 has high similarity to human RecQ4 and was therefore assigned to the RecQ-like helicase family. MrfA homologues appear to be missing in Enterobacteria, however, certain pathogenic Escherichia coli and Salmonella strains harbour Z5898-like helicases with this domain [InterPro reference PUB00098193].
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 |
|---|---|---|---|
| P0DW06 | DISARM protein DrmB Bacillus paralicheniformis (strain ATCC 9945a / NCIMB 11709 / CD-2) | 561 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| P50830 | Mitomycin repair factor A Bacillus subtilis (strain 168) | 749 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| Q05549 | ATP-dependent helicase HRQ1 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) | 1077 aa; version 1 UniProt 2026_03 | PTM REGISTRY MIRROR2 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
- 11,160
- matches
- 11,161
- proteomes
- 8,342
- taxa
- 13,990
- structures
- 5
- alphafold models
- 5,747
- domain architectures
- 99
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 |
|---|---|---|---|---|
| MZB (PF09369) | TraitMech | DISARM system | record mentions previous pfam name |
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.