Messenger RNA-programmed incorporation of multiple N-methyl-amino acids into linear and cyclic peptides.
Kawakami T, Murakami H, Suga H.
Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
Natural peptide products often contain N-methylated backbones, and such a modification plays a crucial role in making natural peptides peptidase resistant and membrane permeable. Here, we demonstrate the ribosomal synthesis of N-methyl-peptides by means of genetic code reprogramming. Two key technologies, a ribozyme-based de novo tRNA acylation (flexizyme) system and an E. coli reconstituted cell-free translation (PURE) system, were used in order to reassign arbitrarily chosen codons to N(alpha)-methylated amino acids ((Me)aa). Using this combination, we determined the general structural requirement of "accessible"(Me)aa and demonstrated their multiple incorporations into the nascent peptide chain according to the assignments made on mRNA, giving linear and cyclic N-methyl-peptides in high purities. This platform technology offers a convenient tool for the construction of N-methyl-peptide libraries, potentially leading to the discovery of therapeutic peptides.
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PMID: 18215771 [PubMed - indexed for MEDLINE]