Design and Characterization of a Methionineless Variant of Thermostable Chaperon GroEL from Thermus thermophilus

Abstract

The GroEL chaperon is of significant interest due to its structure and function, which evolved to facilitate protein folding, and its potential application in artificial expression systems to obtain soluble recombinant proteins. A GroEL variant derived from Thermus thermophilus in which all methionine residues were substituted for leucine was created. This modified chaperon was purified to homogeneity. GroEL completely retained its quaternary structure of the original chaperon (double heptamer), together with its thermostable properties. Both the structure of the new chaperon and its usage as a carrier to obtain target recombinant proteins are attractive for researchers in the field. Also, the substitution of methionine residues in a carrier protein substantially simplifies target protein purification.