Structural and functional response to mutations at the protein-protein interface of mu class glutathione transferase

In order to establish the contribution of specific residues to the stabilit y and folding of a protein, an approach combining protein engineering and e quilibrium unfolding was used. The crystal structures of the alpha, mu and pi class glutathione transferases all show the presence of a conserved phen ylalanine residue at the dimer interface (Phe 47, pi; Phe56, mu; Phe 51, al pha) involved in a lock-and-key interaction. The contribution of this inter action to protein stabilization and dimerization was investigated, by mutat ing the strategic lock residue (phenylalanine) to serine, arginine and glut amic acid. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.