Identification of a GroES (CPN10)-related sequence motif in the GroEL (CPN60) chaperonins

Significant sequence similarity has been noted between a segment of the 60 kDa heat shock family of proteins (designated as GroEL, cpn60 or hsp60) and its functional partner, the 10-12 kDa GroES (or cpn10) family of proteins. Upon introduction of a few gaps, 31 identical and 19 conserved residues were observed in a 93 amino acid overlap between the region comprising of a.a. 314 to 431 in E. coli GroEL and the entire GroES sequence from Bacillus subtilis. The functional forms of both GroEL and GroES proteins, which function as a team in the protein folding process, are toroidal rings exhibiting a highly unusual seven-fold rotational axis of symmetry. It is suggested that the information for assuming this structural form is contained within the shared sequence region between these proteins.