Consecutive βAmino Acids

Due to their unique characteristics, which are not shared by canonical α-peptides, peptides that contain stretches of consecutive β-amino acids are attractive scaffolds for novel peptide drugs and nanomaterials. Although ribosomal incorporation of single or nonconsecutive β-amino acids into peptides has previously been reported, the incorporation of consecutive β-amino acids has not yet been accomplished, primarily due to their incompatibility with the ribosomal translation system.

Researchers in Hiraoki Suga's Laboratory, published in JACS, took advantage of engineered β-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 β-amino acids could be incorporated into a model peptide. Furthermore, the group also demonstrated the synthesis of macrocyclic β-peptides closed by a thioether bond between two d-α-amino acids.

This represents the first example of the ribosomal synthesis of peptides containing stretches of consecutive β-amino acids.

Ribosomal Incorporation of Consecutive βAmino Acids
Takayuki Katoh and Hiroaki Suga
J. Am. Chem. Soc. 2018, 140, 12159-12167