InterPro domain: IPR036386

This superfamily represents the C-terminal oligomerisation domain found in HscB (heat shock cognate protein B), which is also known as HSC20 (20K heat shock cognate protein) and J-protein Jac1 in yeast mitochondria [ 1 ]. HscB acts as a co-chaperone to regulate the ATPase activity and peptide-binding specificity of the molecular chaperone HscA, also known as HSC66 (HSP70 class). HscB proteins contain two domains, an N-terminal J-domain, which is involved in interactions with HscA, connected by a short loop to the C-terminal oligomerisation domain; the two domains make contact through a hydrophobic interface. The core of the oligomerisation domain is thought to bind and target proteins to HscA and consists of an open, three-helical bundle [ 2 ]. HscB, along with HscA, has been shown to play a role in the biogenesis of iron-sulphur proteins.

1. Interaction of J-protein co-chaperone Jac1 with Fe-S scaffold Isu is indispensable in vivo and conserved in evolution. J. Mol. Biol. 417, 1-12
2. Crystal structure of Hsc20, a J-type Co-chaperone from Escherichia coli. J. Mol. Biol. 304, 835-45