Highly efficient solid phase synthesis of large polypeptides by iterative ligations of bis(2-sulfanylethyl)amido (SEA) peptide segments

Up to now, the advantages of solid phase protein synthesis have been largely under-utilized due to the difficulty of designing a simple and efficient elongation cycle enabling the concatenation of unprotected peptide segments. The combination of selective N-terminal anchoring (N-3-Esoc linker) with the blocked thioester properties of the SEA(off) group enabled the solid phase concatenation of unprotected peptide segments by N-to-C sequential formation of native peptide bonds. The strategy was applied to the synthesis of a 60 amino acid-long latent peptide thioester or to the assembly of five peptide segments to give a 15 kDa polypeptide.