Molecular Mimicry in Protein Synthesis?

摘要

This week's issue of Science includes the first report by the Aarhus group of the crystal structure of elongation factor Tu (EF-Tu) complexed with aminoacylated phenylalanyl transfer RNA (tRNA) and guanosine tri-phosphate (GTP)—the EF-Tu ternary complex (1). EF-Tu and its eukaryotic homolog EF-1alpha deliver aminoacyl tRNAs to the ribosome during the elongation phase of protein synthesis (see figure). In addition to providing insights into the way aminoacyl tRNAs get to the ribosome, this structureaddresses a long-standing, mechanistic question: Why does EF-Tu deliver only aminoacylated elongator tRNAs to the ribosome, never uncharged tRNAs or initiator tRNAs? Both because of the biological importance of protein synthesis and because of the long scientific history of this complex, the publication of its structure is a landmark.