Chaperonins are proteins that provide favourable conditions for the correct folding of other proteins, thus preventing aggregation. They prevent the misfolding of proteins, which prevents diseases such as Mad Cow Disease. Newly made proteins usually must fold from a linear chain of amino acids into a three-dimensional form. Chaperonins belong to a large class of molecules that assist protein folding, called molecular chaperones. The energy to fold proteins is supplied by adenosine triphosphate (ATP). Chaperonin proteins may also tag misfolded proteins to be degraded. Chaperonins are proteins that provide favourable conditions for the correct folding of other proteins, thus preventing aggregation. They prevent the misfolding of proteins, which prevents diseases such as Mad Cow Disease. Newly made proteins usually must fold from a linear chain of amino acids into a three-dimensional form. Chaperonins belong to a large class of molecules that assist protein folding, called molecular chaperones. The energy to fold proteins is supplied by adenosine triphosphate (ATP). Chaperonin proteins may also tag misfolded proteins to be degraded.