Unique animal prenyltransferase with monoterpene synthase activity

Abstract

Monoterpenes are structurally diverse natural compounds that play an essential role in the chemical ecology of a wide array of organisms. A key enzyme in monoterpene biosynthesis is geranyl diphosphate synthase (GPPS). GPPS is an isoprenyl diphosphate synthase that catalyzes a single electrophilic condensation reaction between dimethylallyl diphosphate (C(5)) and isopentenyl diphosphate (C(5)) to produce geranyl diphosphate (GDP; C(10)). GDP is the universal precursor to all monoterpenes. Subsequently, monoterpene synthases are responsible for the transformation of GDP to a variety of acyclic, monocyclic, and bicyclic monoterpene products. In pheromone-producing male Ips pini bark beetles (Coleoptera: Scolytidae), the acyclic monoterpene myrcene is required for the production of the major aggregation pheromone component, ipsdienol. Here, we report monoterpene synthase activity associated with GPPS of I. pini. Enzyme assays were performed on recombinant GPPS to determine the presence of monoterpene synthase activity, and the reaction products were analyzed by coupled gas chromatography-mass spectrometry. The functionally expressed recombinant enzyme produced both GDP and myrcene, making GPPS of I. pini a bifunctional enzyme. This unique insect isoprenyl diphosphate synthase possesses the functional plasticity that is characteristic of terpene biosynthetic enzymes of plants, contributing toward the current understanding of product specificity of the isoprenoid pathway.

Frontalin pheromone biosynthesis in the mountain pine beetle, Dendroctonus ponderosae , and the role of isoprenyl diphosphate synthases

“…DponGPPS/FPPS and DponGGPPS shared 28% and 16% amino acid identity, respectively, with the GPPS/myrcene synthase (IpinGPPS/ MS) from I. pini (13). We found no evidence for an ortholog of this unique I. pini gene (14) in the genome or transcriptome of MPB. PstrGGPPS shared 77% amino acid identity with DponGGPPS.…”

“…In addition, an ortholog to the I. pini GPPS/MS (13) could not be found in the MPB genome (22) or in the MPB, SPB, or WPW transcriptome assemblies (NCBI TSA accession no. GAEO00000000) (25,26), reinforcing the unique role that IpinGPPS/MS plays in pheromone biosynthesis in I. pini (13,14).…”

“…These isoprenyl diphosphates are biosynthesized from the five-carbon precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) by the isoprenyl diphosphate synthases (IDSs) GPP synthase (GPPS), FPP synthase (FPPS), and GGPP synthase (GGPPS). However, it is not known which of these isoprenyl diphosphates is used as a precursor in frontalin biosynthesis.A few IDSs have been characterized in Coleoptera, including an FPPS from the cotton boll weevil (Anthonomus grandis) (11), a GPPS/FPPS from the horseradish leaf beetle (Phaedon cochleariae) (12), and a unique GPPS from the pine engraver beetle (Ips pini) that also produces myrcene (13,14). To assess their importance in pheromone biosynthesis, we identified and functionally characterized two IDSs in MPB.…”

“…A few IDSs have been characterized in Coleoptera, including an FPPS from the cotton boll weevil (Anthonomus grandis) (11), a GPPS/FPPS from the horseradish leaf beetle (Phaedon cochleariae) (12), and a unique GPPS from the pine engraver beetle (Ips pini) that also produces myrcene (13,14). To assess their importance in pheromone biosynthesis, we identified and functionally characterized two IDSs in MPB.…”

Chrysanthemyl Diphosphate Synthase Operates in Planta as a Bifunctional Enzyme with Chrysanthemol Synthase Activity

“…␣-Farnesene synthase from apple (Malus domestica) could take both FPP (C 15 ) or GPP (C 10 ) and IPP (C 5 ) to produce ␣-farnesene (C 15 ), and both activities were associated with the (semi)conserved DDXXD motif (23), which is required for metal ion binding (24). Myrcene synthase from bark beetle (Ips pini) was initially identified as a GDS (25) but was later discovered to take GDP to further produce myrcene (C 10 ) (26). The authors predicted that both prenyltransferase and terpene synthase activities shared the same catalytic domain on the basis of modeling of the protein structure.…”