InterPro domain: IPR019591

This entry contains cytosolic Fe-S cluster assembling factors NBP35 and CFD1. The NBP35-CFD1 heterotetramer forms a Fe-S scaffold complex, mediating the de novo assembly of an Fe-S cluster and its transfer to target apoproteins. Nucleotide binding and hydrolysis seems to be critical for loading of Fe-S clusters onto CFD1 and NBP35 [ 1 , 2 , 3 ]. In higher eukaryotes NBP35 and CFD1 are known as NUBP1 and NUBP2, and NUBP1 is also involved in iron regulation [ 4 ].

Bacterial homologues ApbC and MRP (Multiple Resistance and pH adaptation in E. coli) have been shown to contain an ATP-binding domain at the N terminus and have ATPase activity. MRP is a membrane-spanning protein and functions as a Na+/H+ antiporter [ 5 , 6 ]. Archaeal homologues function as iron-sulfur cluster carriers [ 7 ].

1. The eukaryotic P loop NTPase Nbp35: an essential component of the cytosolic and nuclear iron-sulfur protein assembly machinery. Proc. Natl. Acad. Sci. U.S.A. 102, 3266-71
2. Nar1p, a conserved eukaryotic protein with similarity to Fe-only hydrogenases, functions in cytosolic iron-sulphur protein biogenesis. Biochem. Soc. Trans. 33, 86-9
3. Functional link between ribosome formation and biogenesis of iron-sulfur proteins. EMBO J. 24, 580-8
4. Human Nbp35 is essential for both cytosolic iron-sulfur protein assembly and iron homeostasis. Mol. Cell. Biol. 28, 5517-28
5. mrp, a multigene, multifunctional locus in Bacillus subtilis with roles in resistance to cholate and to Na+ and in pH homeostasis. J. Bacteriol. 181, 2394-402
6. The Mrp Na+/H+ antiporter increases the activity of the malate:quinone oxidoreductase of an Escherichia coli respiratory mutant. J. Bacteriol. 187, 388-91
7. Archaeal ApbC/Nbp35 homologs function as iron-sulfur cluster carrier proteins. J. Bacteriol. 191, 1490-7