Enantiomeric ligase is another critical enzyme that can be used to create long stretches of L-DNA. Preparation of a mirror-image ribosome is exceptionally challenging as it composes of multiple protein and nucleotide subunits. Currently, three enantiomeric ribosomal proteins of the large subunit of the E. coli ribosome have been reported, including L5, L18 and L25. The Dribosomal proteins were prepared with native post-translational modifications and interacted specifically with L-5S RNA to form a mirror-image ribonucleoprotein complex. On the other hand, eukaryotic ribosomes consist of 79-80 proteins and four rRNAs, requiring approximately 200 non-ribosomal factors for assembly. Both the ribosomal proteins and rRNA itself also bear post-translational modifications, adding further challenges to their preparation.