InterPro domain: IPR027410

Chaperonins are large cylindrical structures that transiently enclose a partially folded polypeptide and allow it to continue folding in a sequestered environment. Chaperonins are grouped into two families: group I chaperonins, found in eubacteria (e.g. GroEL in Escherichia coli) and eukaryotic organelles of eubacterial descent (e.g. Cpn60 in mitochondria and chloroplasts), and group II chaperonins, found in archaea and the eukaryotic cytosol (CCT or TCP-1 complex) [ 1 , 2 ]. Both groups share a common monomer architecture of three domains: an equatorial domain that carries ATPase activity, an intermediate domain, and an apical domain, involved in substrate binding [ 3 , 4 ].

This superfamily represents the intermediate domain of type II chaperonins.

1. Assembly of chaperonin complexes. Mol. Biotechnol. 19, 141-52
2. The chaperonin containing t-complex polypeptide 1 (TCP-1). Multisubunit machinery assisting in protein folding and assembly in the eukaryotic cytosol. Eur. J. Biochem. 230, 3-16
3. The chaperonin ATPase cycle: mechanism of allosteric switching and movements of substrate-binding domains in GroEL. Cell 87, 241-51
4. Crystal structure of the CCTgamma apical domain: implications for substrate binding to the eukaryotic cytosolic chaperonin. J. Mol. Biol. 318, 1367-79