P100 Structural and Biochemical Characterization of the ATP-Binding YcaO Domain
Monday, July 21, 2014
Jonathan R. Chekan1, Kyle L. Dunbar2, Courtney L. Cox3, Brandon J. Burkhart2, Douglas A. Mitchell2 and Satish K. Nair1, (1)Department of Biochemistry, University of Illinois Urbana Champaign, Urbana, IL, (2)Department of Chemistry, University of Illinois Urbana Champaign, Urbana, IL, (3)Department of Microbiology, University of Illinois Urbana Champaign, Urbana, IL
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 enzymes, while 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 that is conserved among TOMM YcaOs and is required for cyclodehydration. This study identifies the YcaO active site and paves the way for the characterization of the numerous YcaO domains not associated with TOMM biosynthesis.