Structure of limonene synthase, a simple model for terpenoid cyclase catalysis

Abstract

The crystal structure of (4S)-limonene synthase from Mentha spicata, a metal ion-dependent monoterpene cyclase that catalyzes the coupled isomerization and cyclization of geranyl diphosphate, is reported at 2.7-Å resolution in two forms liganded to the substrate and intermediate analogs, 2-fluorogeranyl diphosphate and 2-fluorolinalyl diphosphate, respectively. The implications of these findings are described for domain interactions in the homodimer and for changes in diphosphate-metal ion coordination and substrate binding conformation in the course of the multistep reaction. © 2007 by The National Academy of Sciences of the USA.