All families / PF01982
PF01982: CTP-dep_RFKase
Domain of unknown function DUF120
- Curation status
- SEEDED
- Seed status
- EX DUF
- Characterization
- UNSCORED
Grounding
PF01982: Domain of unknown function DUF120
IPR023602: integrated entry for Domain of unknown function DUF120
Source description
This domain is a CTP-dependent riboflavin kinase (RFK), found in archaea, that catalyses the phosphorylation of riboflavin to form flavin mononucleotide in riboflavin biosynthesis [ec:2.7.1.26]. Its structure resembles a RIFT barrel, structurally similar to but topologically distinct from bacterial and eukaryotic examples. The N-terminal is a winged helix-turn-helix DNA-binding domain, and the C-terminal half is most similar in sequence to a group of cradle-loop barrels. O28174 (UniProtKB protein) has this domain attached to PF00325 (Pfam entry).
Evidence and references
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
5 verified sequence examples. FASTA
| UniProt | Protein / organism | Sequence | Provenance |
|---|---|---|---|
| A2BK57 | Riboflavin kinase Hyperthermus butylicus (strain DSM 5456 / JCM 9403 / PLM1-5) | 149 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| O28174 | Riboflavin kinase Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16) | 233 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| Q3IUQ3 | Riboflavin kinase Natronomonas pharaonis (strain ATCC 35678 / DSM 2160 / CIP 103997 / JCM 8858 / NBRC 14720 / NCIMB 2260 / Gabara) | 232 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| Q5UY62 | Riboflavin kinase Haloarcula marismortui (strain ATCC 43049 / DSM 3752 / JCM 8966 / VKM B-1809) | 320 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| Q60365 | Riboflavin kinase Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) | 132 aa; version 2 UniProt 2026_03 | PTM REGISTRY MIRROR9 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
- 682
- matches
- 683
- proteomes
- 657
- taxa
- 1,274
- structures
- 8
- alphafold models
- 625
- domain architectures
- 18
Classification basis
name matches duf; name says unknown function; domain of unknown function; pfam previous unknown name
No scoring reasons supplied.
Related Mech records
| Family | Mech | Record | Protein | Link basis |
|---|---|---|---|---|
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | riboflavin kinase activity | Q60365 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | FMN biosynthetic process | Q60365 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | riboflavin biosynthetic process | Q60365 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | CTP-dependent riboflavin kinase | Q60365 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | Riboflavin kinase domain, CTP-dependent | Q60365 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | Riboflavin kinase domain, CTP-dependent | trait identifier | |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | Domain of unknown function DUF120 | A2BK57 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | Domain of unknown function DUF120 | O28174 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | Domain of unknown function DUF120 | Q60365 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | Domain of unknown function DUF120 | trait identifier | |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | Helix-turn-helix domain | Q3IUQ3 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | Helix-turn-helix domain | Q5UY62 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | Riboflavin kinase domain superfamily | Q60365 Riboflavin kinase | canonical example family classification |
| CTP-dep_RFKase (PF01982) | ProteinTraitsMech | Riboflavin kinase-like | Q60365 Riboflavin kinase | canonical example family classification |
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.