Chaperonin

Chaperonins, abbreviated Cpn, Cpn60, or HSP60, are a family of heat shock proteins that assist in the folding of newly synthesized proteins and refolding of misfolded proteins during stressful conditions such as high temperature. They are protein complexes consisting of about 16 protein subunits of ~60 kDa each. Chaperonins belong to a large class of molecules and complexes that assist protein folding, called molecular chaperones.

Newly made proteins usually must fold from a linear chain of amino acids into a three-dimensional tertiary structure. The energy to fold proteins is supplied by non-covalent interactions between the amino acid side chains of each protein, and by solvent effects. Most proteins spontaneously fold into their most stable three-dimensional conformation, which is usually also their functional conformation, but occasionally proteins mis-fold. Molecular chaperones catalyze protein refolding by accelerating partial unfolding of misfolded proteins, aided by energy supplied by the hydrolysis of adenosine triphosphate (ATP). Chaperonin proteins may also tag misfolded proteins to be degraded.