Ribozyme synthesis of both L- and D- amino acid oligos

The ribosome is responsible for assembling proteins using 20 naturally occurring L-handed amino acids. However, incorporating non-natural amino acids into a protein is a challenging process needs improvement. In this study, we report a new possible approach to creating nonnatural peptides using ribozymes inspired by the peptidyl transfer center. These RNA scaffolds, which are approximately 100 nucleotides in length, bind to RNase T1 truncated tRNA-like chimeras and bring them into close proximity to facilitate peptide ligation. We used single-molecule fluorescence resonance energy transfer (smFRET) to show close distances between RNA-RNA, tRNA^Lys-tRNA^Lys, and RNA-tRNA^Lys pairs, which strongly suggests that the mechanism of peptide ligation is due to the proximity of the substrate through dimerization of the enzymes. Mass spectrometry analysis confirmed the detection of oligopeptides from four amino acids, including L-Lysine, D-Lysine, L-Phenylalanine, and D-Phenylalanine. These results indicate that ribozymes have greater flexibility in accommodating nonnatural amino acids. Our findings pave the way for potentially new avenues in the synthesis of nonnatural peptides, beyond the limitations of ribosomal peptide synthesis and other existing methods.