<p>Translation elongation factors are responsible for two main processes during protein synthesis on the ribosome [<cite idref="PUB00033953"/>, <cite idref="PUB00033952"/>, <cite idref="PUB00033951"/>]. EF1A (or EF-Tu) is responsible for the selection and binding of the cognate aminoacyl-tRNA to the A-site (acceptor site) of the ribosome. EF2 (or EF-G) is responsible for the translocation of the peptidyl-tRNA from the A-site to the P-site (peptidyl-tRNA site) of the ribosome, thereby freeing the A-site for the next aminoacyl-tRNA to bind. Elongation factors are responsible for achieving accuracy of translation and both EF1A and EF2 are remarkably conserved throughout evolution.</p><p>EF1A (also known as EF-1alpha or EF-Tu) is a G-protein. It forms a ternary complex of EF1A-GTP-aminoacyltRNA. The binding of aminoacyl-tRNA stimulates GTP hydrolysis by EF1A, causing a conformational change in EF1A that causes EF1A-GDP to detach from the ribosome, leaving the aminoacyl-tRNA attached at the A-site. Only the cognate aminoacyl-tRNA can induce the required conformational change in EF1A through its tight anticodon-codon binding [<cite idref="PUB00033960"/>, <cite idref="PUB00033961"/>]. EF1A-GDP is returned to its active state, EF1A-GTP, through the action of another elongation factor, EF1B (also known as EF-Ts or EF-1beta/gamma/delta).</p><p>This entry represents EF1A proteins found primarily in eukaryotic (eEF1A) and archaeal (aEF1A) organisms, these proteins being more closely related to one another than to EF1A (or EF-Tu) found in bacteria (<db_xref db="INTERPRO" dbkey="IPR004541"/>).</p><p>More information about these proteins can be found at Protein of the Month: Elongation Factors [<cite idref="PUB00033962"/>].</p>