Synthesis of fused tricyclic peptides using a reprogrammed translation system and chemical modification

Abstract

Here we report a unique method of ribosomally synthesizing fused tricyclic peptides. Flexizyme-assisted in vitro translation of a linear peptide with the N-terminal chloroacetyl group and four downstream cysteines followed by the addition of 1,3,5-tris(bromomethyl)benzene results in selective production of the fused tricyclic peptide. This technology can be used for the ribosomal synthesis of fused tricyclic peptide libraries for the in vitro selection of bioactive peptides with tricyclic topology.

Conformational Restriction of Peptides Using Dithiol Bis-Alkylation

“…A novel method was reported by the Suga lab where they synthesized tricyclic peptides using flexizyme-assisted translation (Goto, Katoh, & Suga, 2011) and the tmb linker (Bashiruddin, Nagano, & Suga, 2015). With this technology, they replaced the N-terminal methionine with a chloroacetyl-containing amino acid, which spontaneously macrocyclizes by forming a thioether bond with a nonadjacent cysteine.…”

“…With this technology, they replaced the N-terminal methionine with a chloroacetyl-containing amino acid, which spontaneously macrocyclizes by forming a thioether bond with a nonadjacent cysteine. The three remaining cysteines were then cyclized using the tmb linker to form tricyclic peptides (Bashiruddin et al, 2015). …”

Linker-free incorporation of carbohydrates into in vitro displayed macrocyclic peptides

“…Reaction of an N -chloroacetylated initiator amino acid, incorporated by genetic code reprogramming using the FIT system, 40 with a cysteine thiol is selective for the first downstream cysteine, with the important exception of a cysteine as the second amino acid. 41,42 Cysteine in this second position could thus be used for modification within a macrocyclic peptide. In addition, a cysteine in the linear ‘tail’ outside the macrocyclic region could also be modified.…”

“…42 Briefly, 20 μL translation reactions were subjected to the above general method for post-translational modification of peptides with 5 mM DBAA then 12.5 mM thio-Glc or carboxybenzyl thiol for 3 hours. Macrocyclisation by DSG was also carried out as outlined above.…”

Neue Modalitäten für schwierige Zielstrukturen in der Wirkstoffentwicklung

“…So kann auch eine nicht-natürliche Dithiol-Aminosäure innerhalb einer Peptidsequenz eingefügt werden, um zwei Disulfidbrücken zu bilden (Abbildung 5b). [79] Bicyclische Peptide kçnnen auch zur Stabilisierung von a-Helices oder komplexeren Tertiärstrukturen verwendet werden. Andere Methoden zur Herstellung solcher bicyclischen Gerüste sind z.…”