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 1Bγ (eEF1Bγ), encoded by the TEF3 gene in Saccharomyces cerevisiae, has been determined at 3.0 Å 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 eEF1Bγ has no obvious catalytic residue. However, the second form of eEF1Bγ 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·eEF1Bα·eEF1Bγ]2 complex. A 23-residue sequence in the middle of eEF1Bγ is essential for the stable dimerization of eEF1Bγ and the quaternary structure of the eEF1 complex.