Evolution of the EF-Tu Family

Two recent developments have allowed for the identification of a “family” of EF-Tu-like proteins. The first is the biochemical characterization of several proteins which bind aminoacyl-tRNAs in a GTP-dependent manner. The second has been the identification of sequence identity elements that are similar to EF-Tu and many of which would allow for a similar three dimensional structure. A key element in this second part has been the emergence of a 2.6 Å resolution crystal structure for Escherichia coli EF-Tu (Kjeldgaard and Nyborg, 1992). This report discusses the evolution of prokaryotic EF-Tu into its eukaryotic counterpart EF-la as well as the evolution of EF-Tu into proteins with distinct, but related functional properties. While not all of the family members have been characterized biochemically, based upon their similarity to EF-Tu and the presence of the three GTP consensus elements, it is likely that all the family members function by binding aminoacyl-tRNA in a GTP-dependent manner