A family of multisubunit protein complexes that form into large cylindrical structures which bind to and encapsulate non-native proteins. Chaperonins utilize the energy of ATP hydrolysis to enhance the efficiency of protein folding reactions and thereby help proteins reach their functional conformation. The family of chaperonins is split into group i chaperonins, and group ii chaperonins, with each group having its own repertoire of protein subunits and subcellular preferences.