Single nucleotide translation without ribosomes.

The translation of messenger RNA sequences into polypeptide sequences according to the genetic code is central to life. How this process, which relies on the ribosomal machinery, arose from much simpler precursors is unclear. Here, we demonstrate that single nucleotides charged with an amino acid couple with amino acids linked to the 5′-terminus of an RNA primer in reactions directed by the nucleotides of an RNA template in dilute aqueous solution at 0 °C. When a mixture of U-Val, A-Gly and G-Leu competed for coupling to Gly-RNA, base pairing dictated which dipeptide sequence formed preferentially. The resulting doubly anchored dipeptides can retain their link to the primer for further extension or can be fully released under mild acidic conditions. These results show that a single-nucleotide-based form of translation exists that requires no more than oligoribonucleotides and anchored amino acids. Elucidating the origin of translation—the process that produces a specific peptide from an RNA sequence—is one of the most difficult challenges in prebiotic chemistry and evolutionary biology. Now, it has been shown that aminoacylated nucleotides couple to amino-acid-bearing oligoribonucleotides, directed by an RNA template, forming specific di- and tripeptides in the absence of ribosomal machinery.