The crystal structure of the glutathione S-transferase-like domain of elongation factor 1Bγ from Saccharomyces cerevisiae

The crystal structure of the N- terminal 219 residues ( domain 1) of the conserved eukaryotic translation elongation factor 1Bgamma ( eEF1Bgamma), encoded by the TEF3 gene in Saccharomyces cerevisiae, has been determined at 3.0 Angstrom resolution by the single wavelength anomalous dispersion technique. The structure is overall very similar to the glutathione S- transferase proteins and contains a pocket with architecture highly homologous to what is observed in glutathione S- transferase enzymes. The TEF3- encoded form of eEF1Bgamma has no obvious catalytic residue. However, the second form of eEF1Bgamma encoded by the TEF4 gene contains serine 11, which may act catalytically. Based on the x- ray structure and gel filtration studies, we suggest that the yeast eEF1 complex is organized as an [ eEF1A . eEF1B alpha. eEF1Bgamma](2) complex. A 23-residue sequence in the middle of eEF1Bgamma is essential for the stable dimerization of eEF1Bgamma and the quaternary structure of the eEF1 complex.