Mirror-Image 5S Ribonucleoprotein Complexes.

After realizing mirror-image genetic replication, transcription, and reverse transcription, the biggest challenge in establishing a mirror-image version of the central dogma is to build a mirror-image ribosome-based translation machine. Here, we chemically synthesized the natural and mirror-image versions of three ribosomal proteins (L5, L18, and L25) in the large subunit of the Escherichia coli ribosome with post-translational modifications. We show that the synthetic mirror-image proteins can fold in vitro despite limited efficiency and assemble with enzymatically transcribed mirror-image 5S ribosomal RNA into ribonucleoprotein complexes. In addition, the RNA-protein interactions are chiral-specific in that the mirror-image ribosomal proteins do not bind with natural 5S ribosomal RNA and vice versa. The synthesis and assembly of mirror-image 5S ribonucleoprotein complexes are important steps towards building a functional mirror-image ribosome.