Frontiers in Chemistry (Sep 2022)

Synthesis of cholera toxin B subunit glycoconjugates using site-specific orthogonal oxime and sortase ligation reactions

  • Jonathan P. Dolan,
  • Darren C. Machin,
  • Simone Dedola,
  • Robert A. Field,
  • Robert A. Field,
  • Michael E. Webb,
  • W. Bruce Turnbull

DOI
https://doi.org/10.3389/fchem.2022.958272
Journal volume & issue
Vol. 10

Abstract

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The chemoenzymatic synthesis of a series of dual N- and C-terminal–functionalized cholera toxin B subunit (CTB) glycoconjugates is described. Mucin 1 peptides bearing different levels of Tn antigen glycosylation [MUC1(Tn)] were prepared via solid-phase peptide synthesis. Using sortase-mediated ligation, the MUC1(Tn) epitopes were conjugated to the C-terminus of CTB in a well-defined manner allowing for high-density display of the MUC1(Tn) epitopes. This work explores the challenges of using sortase-mediated ligation in combination with glycopeptides and the practical considerations to obtain high levels of conjugation. Furthermore, we describe methods to combine two orthogonal labeling methodologies, oxime- and sortase-mediated ligation, to expand the biochemical toolkit and produce dual N- and C-terminal–labeled conjugates.

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