Bridging the Gap between Ribosomal and Non-ribosomal Protein Synthesis

Aminoacyl-tRNA synthetases (aaRSs) are the enzymes normally responsible for the attachment of amino acids (aa) to tRNAs. Numerous paralogous proteins of aaRSs have been identified in a wide range of organisms, but the functions of most of these aaRS-like proteins are yet to be determined. In PNAS, the study by Mocibob et al. (1) identifies a paralog of seryl-tRNA synthetase that does not aminoacylate a tRNA, but instead, aminoacylates an aa carrier protein. This exciting discovery provides an unforeseen function for the aaRS architecture and also uncovers a possible evolutionary link between ribosome-catalyzed translation and nonribosomal peptide synthesis