Polypeptide chain folds to native protein under physiological conditions.
At least in vivo , in addition to physiological conditions, certain initial kinetic conditions are also required upon folding. Chaperonin complex provides in the cell for the initial kinetic requirements for co-translational folding of polypeptide chain to native protein in sites in the cytoplasm distant from the ribosome and in the plasma of organelles. The known models of the chaperonin complex structure suggest that it is formed by binding of a dome-like GroES oligomer to the end orifice of the GroEL cylinder via long mobile loops of its base. The proposed complex has the form of coaxial cylinders. It is sufficiently stable and cannot dissociate under physiological conditions.