Heat shock protein 10 chaperonins are co-factors for 60KDa Group I chaperonins, functioning as detachable 'lid' structures on the large ring-like complexes formed by the 60Kda subunits. Together, they catalyse the ATP-dependent folding of proteins in prokaryotes and endosymbiotic organelles such as mitochondria and chloroplasts. (Adapted from
FBrf0232269.)