AN EVOLUTIONARY APPROACH TO THE DESIGN OF GLUTATHIONE-LINKED ENZYMES

Studies of protein structure provide information about principles of p rotein design that have come into play in natural evolution. This info rmation can be exploited in the redesign of enzymes for novel function s. The glutathione-binding domain of glutathione transferases has simi larities with structures in other glutathione-linked proteins, such as glutathione peroxidases and thioredoxin (glutaredoxin), suggesting di vergent evolution from a common ancestral protein fold. In contrast, t he binding site for glutathione in human glyoxalase I is located at th e interface between the two identical subunits of the protein. Compari son with the homologous, but monomeric, yeast glyoxalase I suggests th at new domains have originated through gene duplications, and that the oligomeric structure of the mammalian gryoxalase I has arisen by 'dom ain swapping'. Recombinant DNA techniques are being used for the redes ign of glutathione-linked proteins in attempts to create binding prote ins with novel functions and catalysts with tailored specificities. En zymes with desired properties are selected from libraries of variant s tructures by use of phage display and functional assays. (C) 1998 Else vier Science Ireland Ltd. All rights reserved.