Selection for constrained peptides that bind to a single target protein

Andrew M. King, Daniel A. Anderson, Emerson Glassey, Thomas H. Segall-Shapiro, Zhengan Zhang, David L. Niquille, Amanda C. Embree, Katelin Pratt, Thomas L. Williams, D. Benjamin Gordon, Christopher A. Voigt

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Peptide secondary metabolites are common in nature and have diverse pharmacologically-relevant functions, from antibiotics to cross-kingdom signaling. Here, we present a method to design large libraries of modified peptides in Escherichia coli and screen them in vivo to identify those that bind to a single target-of-interest. Constrained peptide scaffolds were produced using modified enzymes gleaned from microbial RiPP (ribosomally synthesized and post-translationally modified peptide) pathways and diversified to build large libraries. The binding of a RiPP to a protein target leads to the intein-catalyzed release of an RNA polymerase σ factor, which drives the expression of selectable markers. As a proof-of-concept, a selection was performed for binding to the SARS-CoV-2 Spike receptor binding domain. A 1625 Da constrained peptide (AMK-1057) was found that binds with similar affinity (990 ± 5 nM) as an ACE2-derived peptide. This demonstrates a generalizable method to identify constrained peptides that adhere to a single protein target, as a step towards “molecular glues” for therapeutics and diagnostics.

Original languageEnglish (US)
Article number6343
JournalNature Communications
Issue number1
StatePublished - Dec 1 2021

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • General
  • Physics and Astronomy(all)


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