ABSTRACT
The intriguing structure of chaperonins, first indicated by electron microscopy (EM) studies in the late 1970’s, suggested that they would have a novel and fascinating mode of action. The interest of structural biologists and biochemists alike was ensured by the subsequent demonstration of their essential biological function of stabilizing unfolded, or partially folded states of a wide range of polypeptides, thus preventing irreversible loss through aggregation, and assisting their folding to a native conformation (Ellis & van der Vies, 1991; Jaenicke, 1993; Clarke, 1996a; Hartl, 1996) (see chapters by Welch et al. and Burkholder and Gottesman). However, the way in which the structural complexity of these macromolecules (approximate molecular mass ~lMDa) is organized to transduce the energy of ATP hydrolysis into the refolding process has presented an enormous challenge to researchers.
