Protein Domain : IPR010236

Type:  Family Name:  ISC system FeS cluster assembly, HscA chaperone
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][]. 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 ISC system is conserved in eubacteria and eukaryotes (mitochondria), and has broad specificity, targeting general FeS proteins [, ]. It is encoded by the isc operon (iscRSUA-hscBA-fdx-iscX). IscS is a cysteine desulphurase, which obtains S from cysteine (converting it to alanine) and serves as a S donor for FeS cluster assembly. IscU and IscA act as scaffolds to accept S and Fe atoms, assembling clusters and transfering them to recipient apoproteins. HscA is a molecular chaperone and HscB is a co-chaperone. Fdx is a [2Fe-2S]-type ferredoxin. IscR is a transcription factor that regulates expression of the isc operon. IscX (also known as YfhJ) appears to interact with IscS and may function as an Fe donor during cluster assembly [].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 []. SufC is an ATPase with an unorthodox ATP-binding cassette (ABC)-like component. No specific functions have been assigned to SufB and SufD. SufA is homologous to IscA [], 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.In the NIF system, NifS and NifU are required for the formation of metalloclusters of nitrogenase in Azotobacter vinelandii, and other organisms, as well as in the maturation of other FeS proteins. Nitrogenase catalyses the fixation of nitrogen. It contains a complex cluster, the FeMo cofactor, which contains molybdenum, Fe and S. NifS is a cysteine desulphurase. NifU binds one Fe atom at its N-terminal, assembling an FeS cluster that is transferred to nitrogenase apoproteins []. Nif proteins involved in the formation of FeS clusters can also be found in organisms that do not fix nitrogen [].This entry represents the HscA chaperone protein from the SUF system. HscA (or Hsc66) is a specialised bacterial Hsp70-class molecular chaperone that participates in the assembly of iron-sulphur cluster proteins. HscA resembles DnaK, but belongs to a separate clade. HscA interacts with IscU, which is believed to serve as a template for Fe-S cluster formation. The HscA-IscU interaction is facilitated by the J-type co-chaperone protein HscB (or Hsc20), which binds to both HscA and IscU, bringing them into contact with each other. HscA recognises a conserved LPPVK sequence motif at positions 99-103 of IscU []. Short Name:  ISC_FeS_clus_asmbl_HscA
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0 Child Features

1 Contains

DB identifier Type Name
IPR018181 Conserved_site Heat shock protein 70, conserved site

2 Cross Referencess

Identifier
TIGR01991
MF_00679

0 Found In

5 GO Annotations

GO Term Gene Name
GO:0005524 IPR010236
GO:0016887 IPR010236
GO:0051082 IPR010236
GO:0006457 IPR010236
GO:0016226 IPR010236

5 Ontology Annotations

GO Term Gene Name
GO:0005524 IPR010236
GO:0016887 IPR010236
GO:0051082 IPR010236
GO:0006457 IPR010236
GO:0016226 IPR010236

1 Parent Features

DB identifier Type Name
IPR013126 Family Heat shock protein 70 family

6 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
Araha.11756s0261.1.p PAC:28856474 Arabidopsis halleri 558  
Brdisv1pangenome1001096m.p PAC:33598969 Brachypodium distachyon Pangenome 605  
Brdisv1pangenome1003453m.p PAC:33619564 Brachypodium distachyon Pangenome 745  
Brdisv1BdTR8i1043912m.p PAC:34241352 Brachypodium distachyon BdTR8i 609  
Brdisv1BdTR11A1024726m.p PAC:35648967 Brachypodium distachyon BdTR11a 745  
Brdisv1BdTR11A1009809m.p PAC:35664308 Brachypodium distachyon BdTR11a 605  

9 Publications

First Author Title Year Journal Volume Pages PubMed ID
            8875867
            11498000
            16221578
            16211402
            15278785
            16843540
            15937904
            17350000
            15100228