Transfer allyl esters to thioesters in solid phase condition: synthesis of peptide thioesters by Fmoc chemistry

Leveraging the Mukaiyama oxidation-reduction condensation reaction for on-resin aryl thio-esterification for bio-conjugation

A room-temperature Mukaiyama oxidation-reduction condensation inspired thioesterification methodology has been developed to afford aryl Cα-terminal peptide thioesters on-resin. The conditions herein feature mild reactions compatible with all Fmoc-SPPS protocols offering direct access to this critical arylthioester scaffold. This one-pot synthesis to aryl-thioester functionalised peptides facilitates peptide/protein synthesis by native chemical ligation.

Safety-catch linkers for Fmoc solid-phase synthesis of peptide thioesters and hydrazides by amide-to-imide activation

The use of C-terminal peptide thioesters and hydrazides in synthetic protein chemistry has inspired the search for optimal solid-phase peptide synthesis (SPPS) strategies for their assembly. However, peptide thioesters are not directly accessible by conventional Fmoc-SPPS owing to the nucleophilicity of the secondary amine required for Fmoc removal. Here, we report the mild and effective activation of the pGlu linker and a new safety-catch linker that was used for the convenient synthesis of peptide thioesters and hydrazides via efficient amide-to-imide activation followed by nucleophilic displacement.

N-Sulfanylethylaminooxybutyramide (SEAoxy): A Crypto-Thioester Compatible with Fmoc Solid-Phase Peptide Synthesis

An N-sulfanylethylaminooxybutyramide (SEAoxy) has been developed as a novel thioester equivalent for native chemical ligation. SEAoxy peptide was straightforwardly synthesized by conventional Fmoc solid-phase peptide synthesis without a problem. Moreover, SEAoxy peptide could be directly applied to native chemical ligation owing to the intramolecular N-to-S acyl shift that releases the peptide-thioester in situ. This methodology was successfully applied to the synthesis of two bioactive peptides.

Synthesis of C-terminal peptide thioesters using Fmoc-based solid-phase peptide chemistry

This chapter provides two protocols for the solid-phase synthesis of peptide thioesters using N (α) -Fmoc-protected amino acids. The first protocol is based on a so-called safety-catch linker, while the second relies on a backbone amide linker.

Chemical control of biomolecular interaction modules

The mutual recognition of biomacromolecules often is mediated by dedicated interaction modules. We take two main approaches in order to recognize and control nucleic acid-nucleic acid, protein-protein, and protein-nucleic acid interactions. In one, the rules that govern the formation of nucleic acid structures are used to design molecules that respond to the presence of nucleic acid or protein targets by showing changes of conformation or reactivity. For example, hybrid molecules can transduce changes of nucleic acid structure to changes of peptide structure, and vice versa. The other approach takes advantage of protein domains that once may form the basis of sensor materials and control elements. However, the current chemical synthesis methods have still not reached the level of maturity required to provide routine access to folded protein domains. In this article, we also describe recent progress that may facilitate the chemical synthesis of protein interaction domains.