 Domain 3 represents the C-terminal domain, which adopts a beta-barrel structure, and is involved in binding to both charged tRNA and to EF1B (or EF-Ts).The GTP-binding domain is conserved in both EF-1alpha/EF-Tu and also in EF-2/EF-G and thus seems typical for GTP-dependent proteins which bind non-initiator tRNAs to the ribosome.The GTP-binding protein synthesis factor family also includes the eukaryotic peptide chain release factor GTP-binding subunits and prokaryotic peptide chain release factor 3 (RF-3); the prokaryotic GTP-binding protein lepA and its homologue in yeast (GUF1) and "Caenorhabditis elegans" (ZK1236.1); yeast HBS1; rat statin S1; and the prokaryotic selenocysteine-specific elongation factor selB.