Enzymatic Pyridine Aromatization during Thiopeptide Biosynthesis

Andrew J. Rice, Jarrett M. Pelton, Nicholas J. Kramer, Daniel S. Catlin, Satish K. Nair, Taras V. Pogorelov, Douglas A. Mitchell, Albert A. Bowers

Research output: Contribution to journalArticlepeer-review

Abstract

Thiazole-containing pyritides (thiopeptides) are ribosomally synthesized and post-translationally modified peptides (RiPPs) that have attracted interest owing to their potent biological activities and structural complexity. The class-defining feature of a thiopeptide is a six-membered, nitrogenous heterocycle formed by an enzymatic [4 + 2]-cycloaddition. In rare cases, piperidine or dehydropiperidine (DHP) is present; however, the aromatized pyridine is considerably more common. Despite significant effort, the mechanism by which the central pyridine is formed remains poorly understood. Building on our recent observation of the Bycroft-Gowland intermediate (i.e., the direct product of the [4 + 2]-cycloaddition), we interrogated thiopeptide pyridine synthases using a combination of targeted mutagenesis, kinetic assays, substrate analogs, enzyme-substrate cross-linking, and chemical rescue experiments. Collectively, our data delineate roles for several conserved residues in thiopeptide pyridine synthases. A critical tyrosine facilitates the final aromatization step of pyridine formation. This work provides a foundation for further exploration of the [4 + 2]-cycloaddition reaction and future customization of pyridine-containing macrocyclic peptides.

Original languageEnglish (US)
Pages (from-to)21116-21124
Number of pages9
JournalJournal of the American Chemical Society
Volume144
Issue number46
DOIs
StatePublished - Nov 23 2022

ASJC Scopus subject areas

  • General Chemistry
  • Biochemistry
  • Catalysis
  • Colloid and Surface Chemistry

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