Discovery of a new ATP-binding motif involved in peptidic azoline biosynthesis

Kyle L. Dunbar, Jonathan R. Chekan, Courtney L. Cox, Brandon J. Burkhart, Satish K. Nair, Douglas A. Mitchell

Research output: Contribution to journalArticlepeer-review


Despite intensive research, the cyclodehydratase responsible for azoline biogenesis in thiazole/oxazole-modified microcin (TOMM) natural products remains enigmatic. The collaboration of two proteins, C and D, is required for cyclodehydration. The C protein is homologous to E1 ubiquitin-activating enzymes, whereas the D protein is within the YcaO superfamily. Recent studies have demonstrated that TOMM YcaOs phosphorylate amide carbonyl oxygens to facilitate azoline formation. Here we report the X-ray crystal structure of an uncharacterized YcaO from Escherichia coli (Ec-YcaO). Ec-YcaO harbors an unprecedented fold and ATP-binding motif. This motif is conserved among TOMM YcaOs and is required for cyclodehydration. Furthermore, we demonstrate that the C protein regulates substrate binding and catalysis and that the proline-rich C terminus of the D protein is involved in C protein recognition and catalysis. This study identifies the YcaO active site and paves the way for the characterization of the numerous YcaO domains not associated with TOMM biosynthesis.

Original languageEnglish (US)
Pages (from-to)823-829
Number of pages7
JournalNature chemical biology
Issue number10
StatePublished - Oct 1 2014

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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