The antibiotic viomycin as a model peptide for the origin of the co-evolution of RNA and proteins

Viomycin is an RNA-binding peptide antibiotic which inhibits prokaryotic pr otein synthesis and group I intron self-splicing. This antibiotic enhances the activity of the ribozyme derived from the Neurospora crassa VS RNA, and at sub-inhibitory concentrations it induces the formation of group I intro n oligomers. Here, we address the question whether viomycin exerts specific ity in the promotion of RNA-RNA interactions. In an in vitro selection expe riment we tested the ability of viomycin to specifically select molecules o ut of an RNA pool. Group I intron RNA was incubated with a pool of random s equence RNA, or with a pool of RNA molecules which had previously been enri ched for viomycin-binding RNAs. Viomycin was added in order to select viomy cin-binding RNAs and to guide their interaction with the intron RNA resulti ng in recombinant molecules. Viomycin was indeed capable of specifically se lecting RNA molecules which contain viomycin-binding sites promoting recomb ination. These results suggest that small peptides are able to play the rol e of selector molecules in a putative 'RNA World' launching the co-evolutio n of RNA and proteins into an 'RNA-protein World'.