All families / PF01458
PF01458: SUFBD_core
SUF system FeS cluster assembly, SufBD core domain
- Curation status
- SEEDED
- Seed status
- EX DUF
- Characterization
- UNSCORED
Grounding
PF01458: SUF system FeS cluster assembly, SufBD core domain
IPR000825: integrated entry for SUF system FeS cluster assembly, SufBD core domain
Source description
Iron-sulphur (FeS) clusters are important cofactors for numerous proteins involved in electron transfer, in redox and non-redox catalysis, in gene regulation, and as sensors of oxygen and iron. These functions depend on the various FeS cluster prosthetic groups, the most common being [2Fe-2S] and [4Fe-4S] [InterPro reference PUB00035635]. FeS cluster assembly is a complex process involving the mobilisation of Fe and S atoms from storage sources, their assembly into [Fe-S] form, their transport to specific cellular locations, and their transfer to recipient apoproteins. So far, three FeS assembly machineries have been identified, which are capable of synthesising all types of [Fe-S] clusters: ISC (iron-sulphur cluster), SUF (sulphur assimilation), and NIF (nitrogen fixation) systems. The SUF system is an alternative pathway to the ISC system that operates under iron starvation and oxidative stress. It is found in eubacteria, archaea and eukaryotes (plastids). The SUF system is encoded by the suf operon (sufABCDSE), and the six encoded proteins are arranged into two complexes (SufSE and SufBCD) and one protein (SufA). SufS is a pyridoxal-phosphate (PLP) protein displaying cysteine desulphurase activity. SufE acts as a scaffold protein that accepts S from SufS and donates it to SufA [InterPro reference PUB00035639]. SufC is an ATPase with an unorthodox ATP-binding cassette (ABC)-like component. SufA is homologous to IscA [InterPro reference PUB00035640], acting as a scaffold protein in which Fe and S atoms are assembled into [FeS] cluster forms, which can then easily be transferred to apoproteins targets. This entry represents the core domain of SufB and SufD proteins, which are homologous, and form part of the SufBCD complex in the SUF system [InterPro reference PUB00089444]. SufB accepts sulfur transferred from SufE [InterPro reference PUB00089442], whereas SufD may play a role in iron acquisition [InterPro reference PUB00089443].
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 |
|---|---|---|---|
| O32162 | Iron-sulfur cluster assembly protein SufB Bacillus subtilis (strain 168) | 465 aa; version 1 UniProt 2026_03 | UNIPROT FETCH |
| O32165 | Iron-sulfur cluster assembly protein SufD Bacillus subtilis (strain 168) | 437 aa; version 1 UniProt 2026_03 | UNIPROT FETCH |
| P77522 | Iron-sulfur cluster assembly protein SufB Escherichia coli (strain K12) | 495 aa; version 2 UniProt 2026_03 | PTM REGISTRY MIRROR |
| P77689 | Iron-sulfur cluster assembly protein SufD Escherichia coli (strain K12) | 423 aa; version 1 UniProt 2026_03 | PTM REGISTRY MIRROR |
| Q25799 | Iron-sulfur cluster assembly protein SufB Plasmodium falciparum (isolate 3D7) | 470 aa; version 1 UniProt 2026_03 | UNIPROT FETCH |
| Q3E8H7 | Iron-sulfur cluster assembly SufBD family protein ABCI9 Arabidopsis thaliana | 470 aa; version 1 UniProt 2026_03 | UNIPROT FETCH |
| Q60349 | Iron-sulfur cluster assembly SufBD family protein MJ0034 Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) | 316 aa; version 1 UniProt 2026_03 | UNIPROT FETCH |
| Q8IIW9 | Iron-sulfur cluster assembly protein SufD Plasmodium falciparum (isolate 3D7) | 1462 aa; version 1 UniProt 2026_03 | UNIPROT FETCH |
| Q9LQK7 | Protein ABCI7, chloroplastic Arabidopsis thaliana | 475 aa; version 1 UniProt 2026_03 | UNIPROT FETCH |
| Q9ZS97 | Iron-sulfur cluster assembly SufBD family protein ABCI8, chloroplastic Arabidopsis thaliana | 557 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
- 30,443
- matches
- 30,502
- proteomes
- 15,015
- taxa
- 22,322
- structures
- 8
- alphafold models
- 20,235
- domain architectures
- 56
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.