This family of proteins is likely to be involved in the assembly of iron-sulphur clusters. It may function as an adaptor protein. In Escherichia coli IscX forms part of the isc operon, which encodes genes involved in iron-sulphur cluster assembly. Its structure is entirely alpha helical, and it contains a modified wing-helix structure, usually found in DNA-binding proteins. It binds to Fe2+ and Fe3+ ions and to the cysteine desulfurase IscS, the same surface of the protein is involved in both binding to iron and to IscS.