Ribosomal Incorporation of Consecutive β-Amino Acids

摘要

Due to their unique characteristics, which are not shared by canonical a peptides, peptides that contain stretches of consecutive beta-amino acids are attractive scaffolds for novel peptide drugs and nanomaterials. Although ribosomal incorporation of single or nonconsecutive beta-amino acids into peptides has previously been reported, the incorporation of consecutive beta-amino acids has not yet been accomplished. This is primarily due to their incompatibility with the ribosomal translation system. Here, we took advantage of engineered beta-aminoacyl-tRNAs bearing optimized T-stem and D-arm motifs for enhancing binding affinity to EF-Tu and EF-P, respectively. Combined with a reconstituted E. coli translation system and optimized translation factor concentrations, up to seven consecutive beta-amino acids could be incorporated into a model peptide. Furthermore, the synthesis of macrocyclic beta-peptides closed by a thioether bond between two D-alpha-amino acids is also demonstrated. This represents the first example of the ribosomal synthesis of peptides containing stretches of consecutive beta-amino acids.