Canadian Forest Service Publications
Cloning, expression and characterization of an insect geranylgeranyl diphosphate synthase from Choristoneura fumiferana. Insect Biochem. 2013. Barbar, A.; Couture, M.; Sen, S.E.; Béliveau, C.; Nisole, A.; Bipfubusa, M.; Cusson, M. Mol. Biol. 43:947-958.
Issued by: Laurentian Forestry Centre
Catalog ID: 35044
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Geranylgeranyl diphosphate synthase (GGPPS) catalyzes the condensation of the non-allylic diphosphate, isopentenyl diphosphate (IPP; C5), with allylic diphosphates to generate the C20 prenyl chain (GGPP) used for protein prenylation and diterpenoid biosynthesis. Here, we cloned the cDNA of a GGPPS from the spruce budworm, Choristoneura fumiferana, and characterized the corresponding recombinant protein (rCfGGPPS). As shown for other type-III GGPPSs, rCfGGPPS preferred farnesyl diphosphate (FPP; C15) over other allylic substrates for coupling with IPP. Unexpectedly, rCfGGPPS displayed inhibition by its FPP substrate at low IPP concentration, suggesting the existence of a mechanism that may regulate intracellular FPP pools. rCfGGPPS was also inhibited by its product, GGPP, in a competitive manner with respect to FPP, as reported for human and bovine brain GGPPSs. A homology model of CfGGPPS was prepared and compared to human and yeast GGPPSs. Consistent with its enzymological properties, CfGGPPS displayed a larger active site cavity that can accommodate the binding of FPP and GGPP in the region normally occupied by IPP and the allylic isoprenoid tail, and the binding of GGPP in an alternate orientation seen for GGPP binding to the human protein. To begin exploring the role of CfGGPPS in protein prenylation, its transcripts were quantified by qPCR in whole insects, along with those of other genes involved in this pathway. CfGGPPS was expressed throughout insect development and the abundance of its transcripts covaried with that of other prenylation-related genes. Our qPCR results suggest that geranylgeranylation is the predominant form of prenylation in whole C. fumiferana.
Plain Language Summary
Developing strategies and tools to control the spruce budworm (SBW) requires thorough knowledge of the biology of this destructive pest of Canadian fir and spruce forests.
More specifically, the development of new pest control products will benefit from spotlighting knowledge on enzymes that might serve as targets for substances that block their reaction.
From this perspective, work has been undertaken to characterize an enzyme that plays an important role in a vital metabolic process of the SBW. This enzyme is geranylgeranyl diphosphate synthase, or GGPPS. The cloning of GGPPS in order to facilitate its study, along with other enzymes involved in this process in the SBW, has been greatly facilitated by access to the genome sequence of this insect.
This SBW enzyme displays certain characteristics that seem to be unique to this insect. The study concluded that this enzyme is a promising target for the development of specific pest control products.