Center for Structural Genomics of Infectious Diseases

Structure of IDP01304

CSGID target: IDP01304
PDB Id: 4IT5 (NCBI MMDB)
Authors: J.Osipiuk,M.Gu,L.Papazisi,W.F.Anderson,A.Joachimiak,Center For Structural Genomics Of Infectious Diseases (Csgid)
Responsible person: Jerzy Osipiuk
Responsible lab: Argonne National Laboratory
Deposition Date: Jan 17, 2013
Release Date: May 26, 2009

Description: HscB protein (heat shock cognate protein B), also known as Hsc20 (20K heat shock cognate protein), is a co-chaperone regulating 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. HscB, along with HscA, has been shown to play a role in the biogenesis of iron-sulphur proteins. HscA has been shown to specifically bind to a conserved sequence present in the [FeS]-scaffold protein IscU. The interaction of IscU with HscA is regulated by HscB which binds the scaffold protein to assist delivery to the chaperone and stabilize the chaperone-scaffold complex by enhancing chaperone ATPase activity. The HscA/HscB system accelerates transfer of iron-sulfur clusters from the FeS-scaffold protein IscU to acceptor proteins in an ATP-dependent manner. This stimulation occurs at low chaperone/scaffold ratios, suggesting that the chaperones act catalytically.
Functional assignment

Ligand code	Name	Ligand type
MSE		modified residue
175	3,5-dihydro-5-methylidene-4h-imidazol-4-on