X‐ray crystal structure of MonCI, an epoxidase from the monensin biosynthesis pathway

Polycyclic polyether natural products have gathered much attention due to their useful therapeutic properties including antimicrobial, antifungal, and anticancer activities. All polyether natural products contain multiple cyclic ether groups but they vary in the number, size, and arrangement of the cyclic ether groups. The ether rings found in natural polyethers are formed via enzymatic epoxidation and epoxide ring‐opening reactions. We have determined the 1.9 Å resolution crystal structure of MonCI, the flavin‐dependent epoxidase responsible for biosynthesis of the ionophore polyether antibiotic monensin. Our structural and molecular dynamics simulation studies indicate that the shape of the substrate‐binding pocket in MonCI dictates the stereoselectivity of epoxidation. Support or Funding Information The University of Texas System STARs Award