Poster Presentation International Peptide Symposium 2023

Structural effects in aza-peptide bond formation reaction (#339)

Anu Ploom 1 , Meeli Arujõe-Sado 1 , Alla Troska-Palla 1
  1. Institute of Chemistry, University of Tartu, Tartu, Estonia

Aza-peptides are peptide analogues that degrade more slowly in living organisms and are therefore promising drug candidates.1 However, the problems encountered in the synthesis of the aza-peptide bond, especially the low yield and slow reaction, hinder the wider investigation of their bioactive properties.

Our group has kinetically investigated aza-peptide bond formation in model aza-peptides (Fig. 1) by conventional SPPS (solid-phase peptide synthesis) method.2–5 This is one way to experimentally evaluate the difference in the reactivity of the N-terminal amino group of amino acid and aza-amino acids and to study the suitability of the SPPS protocol for aza-peptide bond formation.

Performed kinetic studies showed that standard SPPS protocol cannot be applied directly to aza-peptide synthesis. The reaction efficiency of the aza-peptide bond formation is influenced by the effectiveness of the activator used as well as the steric effect of the side chain of the amino acid (R1) and the aza-amino acid (R). Therefore, it is necessary to develop the synthesis methods for aza-peptides in a direction that would enable more effective acylation of the N-terminal of the aza-amino acid. This is important for the creation of automated aza-peptide synthesis methods, which in turn would provide an opportunity for more comprehensive studies of the bioactivity of these compounds.

 

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 Fig. 1 Model aza-peptide

 

Acknowledgements

This research was supported by Estonian Research Council IUT20-15 and PRG300 grants, and by the Ann Mihkelson Foundation of the Estonian National Culture Foundation. This work was supported by of the project PER ASPERA Graduate School of Functional Materials and Technologies receiving funding from the European Regional Development Fund under project in University of Tartu, Estonia.

 

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References

  1. Fan Cheng, K.; VanPatten, S.; He, M.; Al-Abed, Y. Azapeptides -A History of Synthetic Milestones and Key Examples. Current Medicinal Chemistry 2022, 29 (42), 6336–6358. https://doi.org/10.2174/0929867329666220510214402.
  2. Arujõe, M.; Ploom, A.; Mastitski, A.; Järv, J. Influence of Steric Effects in Solid-Phase Aza-Peptide Synthesis. Tetrahedron Letters 2018, 59 (21), 2010–2013. https://doi.org/10.1016/j.tetlet.2018.04.021.
  3. Arujõe, M.; Ploom, A.; Mastitski, A.; Järv, J. Comparison of Various Coupling Reagents in Solid-Phase Aza-Peptide Synthesis. Tetrahedron Letters 2017, 58 (35), 3421–3425. https://doi.org/10.1016/j.tetlet.2017.07.063.
  4. Troska, A.; Arujõe, M.; Mastitski, A.; Järv, J.; Ploom, A. Steric Impact of Aza-Amino Acid on Solid-Phase Aza-Peptide Bond Synthesis. Tetrahedron Letters 2021, 152973. https://doi.org/10.1016/j.tetlet.2021.152973.
  5. Ploom, A.; Mastitski, A.; Arujõe, M.; Troska, A.; Järv, J. Aza-Peptides: Expectations and Reality. PEAS 2022, 71 (3), 241. https://doi.org/10.3176/proc.2022.3.05.