New Methods for the Chemical Synthesis of Post-Translationally Modified Peptides and Proteins

Many proteins and peptidic natural products carry post-translational modifications (PTMs), which modulate their structure and function. Studying those modifications on a molecular level requires unique and defined PTM patterns, which can be obtained through chemical peptide and protein synthesis. Shorter peptides can be obtained through traditional solid phase peptide synthesis (SPPS) in batch. Flow-SPPS, however, often enables the routine synthesis of longer peptides and can additionally give additional insights to SPPS itself.^[1]

We will first present the chemoenzymatic synthesis of lasso peptide MccJ25 and derivatives thereof.^[2] Flow-SPPS of chemically modified precursor peptides (57 amino acids), followed by in vitro transformation with recombinant maturation enzymes yielded an array of lasso peptides including previously inaccessible side chain and backbone modifications. This rapid access to chemically modified lasso peptides could be used to investigate structure–activity relationships, epitope grafting, and the improvement of therapeutic properties.
Not only peptides, but also proteins can be modified by PTMs. The protein MYC is an intrinsically disordered transcription factor that is upregulated in >50% of cancers and engages in numerous protein-protein interactions. These interactions are often regulated through posttranslational modifications (PTMs) within MYC’s transactivation domain (TAD), most commonly (poly)phosphorylation. In the second part of this presentation, our work on deciphering MYC’s phosphorylation-dependent protein-protein interactions will be presented.^[3] A first step towards this goal was the synthesis of MYC’s TAD, a so-called “difficult sequence”, that is challenging to synthesize and therefore inspired the development of new generally applicable tools for chemical protein synthesis.^[4]


[1]     N. Hartrampf, A. Saebi,^‡ M. Poskus,^‡ Z. P. Gates, A. J. Callahan, A. E. Cowfer, S. Hanna, S. Antilla, C. K. Schissel, A. J. Quartararo, X. Ye, A. J. Mijalis, M. D. Simon, A. Loas, S. Liu, C. Jessen, T. E. Nielsen, B. L. Pentelute, Science 2020, 368, 980–987. 
[2]     K. Schiefelbein, J. Lang, M. Schuster, C. E. Grigglestone, R. Striga, L. Bigler, M. C. Schuman, O. Zerbe, Y. Li, N. Hartrampf; J. Am. Chem. Soc. 2024, 146 (25), 17261–17269.
[3]     E. T. Williams, K. Schiefelbein, M. Schuster, I. M. M. Ahmed, M. De Vries, R. Beveridge, O. Zerbe, N. Hartrampf; Chem. Sci. 2024, 15, 8756–8765.
[4]     H. Bürgisser,^‡ E. T. Williams,^‡ A. Jeandin, R. Lescure, A. Premanand, S. Wang, N. Hartrampf, J. Am. Chem. Soc. 2024, just accepted.