Structure and Mechanism of the Monoterpene Cyclolavandulyl Diphosphate Synthase that Catalyzes Consecutive Condensation and Cyclization. Issue 47 (11th October 2017) - Tomita, Takeo
Abstract: We report the three‐dimensional structure of cyclolavandulyl diphosphate (CLPP) synthase (CLDS), which consecutively catalyzes the condensation of two molecules of dimethylallyl diphosphate (DMAPP) followed by cyclization to form a cyclic monoterpene, CLPP. The structures of apo‐CLDS and CLDS in complex with Tris, pyrophosphate, and Mg 2+ ion were refined at 2.00 Å resolution and 1.73 Å resolution, respectively. CLDS adopts a typical fold for cis‐prenyl synthases and forms a homo‐dimeric structure. An in vitro reaction using a regiospecifically 2 H‐substituted DMAPP substrate revealed the intramolecular proton transfer mechanism of the CLDS reaction. The CLDS structure and structure‐based mutagenesis provide mechanistic insights into this unprecedented terpene synthase. The combination of structural and mechanistic insights advances the knowledge of intricate terpene synthase‐catalyzed reactions. Abstract : A synthase that can do both : Cyclolavandulyl diphosphate (CLPP) synthase (CLDS) catalyzes "head‐to‐middle" condensation of two molecules of dimethylallyl diphosphate (DMAPP) and subsequent cyclization to produce CLPP. The crystal structure of CLDS in complex with Tris, pyrophosphate, and Mg 2+ ion was refined at 1.73 Å resolution. An in vitro reaction using a regiospecifically deuterated DMAPP, the CLDS structure, and mutagenesis provide mechanistic insights into this unique terpene synthase.