title: Extensive reprogramming of the genetic code for genetically encoded synthesis of highly N-alkylated polycyclic peptidomimetics.
abstract: Cyclic structures can increase the proteolytic stability and conformational rigidity of peptides, and N-alkylation of the peptide backbone can make peptides more cell-permeable and resistant to proteolysis. Therefore, cyclic N-alkyl amino acids are expected to be useful building blocks to increase simultaneously these pharmacological properties of peptides. In this study, we screened various cyclic N-alkyl amino acids for their ribosomal incorporation into peptides and identified cyclic N-alkyl amino acids that can be efficiently and successively incorporated. We also demonstrated genetic code reprogramming for reassigning 16 NNU codons to 16 different cyclic N-alkyl amino acids with high fidelity to synthesize highly N-alkylated polycyclic peptidomimetics and an mRNA-displayed library of completely N-alkylated polycyclic peptidomimetics by using our recently developed TRAP (transcription/translation coupled with association of puromycin linker) display. In vitro selection from a highly diverse library of such completely N-alkylated polycyclic peptidomimetics could become a powerful means to discover small-molecule ligands such as drug candidates that can be targeted to biomolecules inside living cells.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan. kawakami@bio.c.u-tokyo.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Kawakami
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ishizawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Murakami
mesh_terms: D000478:Alkylation; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D005818:Genetic Engineering / Q000379:methods*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D010456:Peptides, Cyclic / Q000737:chemistry / Q000378:metabolism*; D057786:Peptidomimetics / Q000737:chemistry / Q000378:metabolism*; D016337:RNA, Catalytic / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D003062:Codon; D010456:Peptides, Cyclic; D057786:Peptidomimetics; D016337:RNA, Catalytic; D012343:RNA, Transfer