Isoprenyl diphosphate synthase

Recently Fujiwara et al. reported on the in vitro polymerization of trans-polyisoprene using the enzymes isopentenyl diphosphate isomerase (IDI) and fra 3-isoprenyl diphosphate synthase (IDS) [271]. IDI catalyzes the interconversion of IPP and DMAPP. IDS can now catalyze the polymerization of IPP from DMAPP as outlined above for the synthesis of natural rubber, and as outlined in Fig. 13a. However, the condensation process is inhibited due to hydrophobic interaction between IDS and hydrocarbon of the longer products. The hydrophobic chain of the elongating product does not readily protrude into the aqueous phase and it tends to interact with the enzyme. To achieve an efficient in vitro synthesis, the authors used an organic-aqueous two-liquid phase system to successfully synthesize (low molecular weight) fran.y-polyisoprene (see Fig. 13b). 

Figure 22-1 Outline of biosynthetic pathways for polyprenyl compounds. Steps e,f, and g and many subsequent steps are catalyzed by isoprenyl diphosphate synthases.

NuralA. H., Tittiger C., Welch W. and Blomquist G. J. (2001) Isolation and characterization of isoprenyl diphosphate synthase from cotton boll weevil. Presented at Annu. Meet. Int. Soc. Chem. Ecol. 18th, Lake Tahoe. 

Longer chain isoprenoids are synthesized via two other isoprenyl diphosphate enzyme systems in mammals [21]. Long E-isoprenyl diphosphate synthase (IDS) produces the side chains of ubiquinone. The length of the side chain varies amongst species, and in humans a C50 synthase has been identified [22]. Dehydrodolichyl diphosphate synthase, the only Z-IDS found in mammals, is responsible for the synthesis of the sugar carriers dohchol and dolichyl phosphate [23]. Plants have additional Z-IDS which can catalyze the production of very long isoprene species, such as natural... 

Wang, K.C., and Ohnnma, S. (2000). Isoprenyl diphosphate synthases. Biochim Biophys Acta 1529 33-48. 

Chen, A., Kroon, P.A. and Poulter, C.D. (1994) Isoprenyl diphosphate synthases protein sequence comparisons, a phylogenetic tree and predictions of secondary structure. Protein Sci., 3, 600-7. 

Schmidt, A. and Gershenzon, J. (2007) Cloning and characterization of isoprenyl diphosphate synthases with famesyl diphosphate and geranylgeranyl diphosphate synthase activity from Norway spruce (Picea abies) and their relation to induced oleoresin formation. Phytochemistry, 68, 2649-59. 

Tarshis, L.C., Protean, P.J., Kellogg, B.A., Sacchettini, J.C. and Poulter, C.D. (1996) Regulation of product chain length by isoprenyl diphosphate synthases. Proc. Natl. Acad. Sci USA, 93, 15018-23. 

Search for Genes Encoding Short Chain Isoprenyl Diphosphate Synthases 8... 

Fig. 1.4 Outline of terpenoid biosynthesis from isopentenyl diphosphate (IPP) via dimethylallyl diphosphate (DMAPP), gcranyl diphosphate (GPP), famesyl diphosphate (FPP) and geranylgcranyl diphosphate (GGPP). These reactions are catalyzed by isoprenyl diphosphate synthases and terpene synthases. The major products of the monoterpene, sesquiterpene, and diterpene pathways that constitute the oleoresm of Picea abies are listed. The general precursor IPP is derived either from the plastidial methylerythritol phosphate (MEP) pathway or the cytosolic mevalonaic pathway.

Considerable research has been carried out on the short chain isoprenyl diphosphate synthases of plants, though our knowledge of these enzymes in conifers is restricted to work on just two species, Abies grandis and Taxus canadensis.All short-chain isoprenyl diphosphate synthases share some basic properties, including an absolute catalytic requirement for a divalent metal ion (usually Mg " ), a pFl optimum near neutrality, K values for both substrates in the 1 -100 pM range and a homodimeric architecture with subunits of 30-50 kDa (except... 

We searched for isoprenyl diphosphate synthase gene sequences in P. abies using a homology-based approach. First, RNA was isolated from bark and wood of methyl jasmonate-treated spruce saplings from a single clone. This was then used as a template for reverse transcriptase PCR carried out with degenerate primers... 

Fig. 1.5 Reactions catalyzed by short chain isoprenyl diphosphate synthases in plants. All use the same precursors, IPP and DMAPP, but the enzymes may reside in different subcelLular compartments. The reactions catalyzed by geranyl diphosphate synthase and geranylgeranyl diphosphate synthase are thought to occur in the plastid, and the reaction catalyzed by farnesyl diphosphate in the cytosol.

Fig. 1.6 Phylogenetic tree of gymnosperm and angiosperm isoprenyl diphosphate synthase sequences. The isolated Picea ahies sequences are marked other isoprcnyl diphosphate synthases sequences are listed according to the major reaction product of the recombinant protein. Abbreviations GPP synthase, geranyl diphosphate synthase FPP synthase, famesyl diphosphate synthase and GGPP synthase, geranyl geranyl diphosphate synthase large su, large subunit of protein small su, small subunit of protein.

Fig. 1.7 Heterologous expression of P abies isoprenyl diphosphate synthases in E. coli after Coomassie stain of an SDS-polyaerylamide gel with extraets from baeteria expressing PalDS, PalDSA, PalDSS, and PaIDS6. Lam M, moleeular mass markers Lane BL21, extracts from bacteria containing only the expression vector without an isoprenyl diphosphate synthase sequence C lanes, bacterial crude extracts P lanes, purified recombinant proteins.

Fig. 1.8 Catalytic activities of the isoprenyl diphosphate synthases PalDSl, PaIDS4, PaIDS5, and PaIDS6 after heterologous expression in colL Products were measured by radio-gas chromatography (plotted in Bequcrcl, upper four panels) and identified by co-injection of non-radioactive terpenc standards, detected via a thermal conductivity detector (plotted as detector response, bottom panel). The main products after acid hydrolysis are listed G, geraniol F, farnesol and GG, geranylgeraniol. Bacteria containing only the expression vector without an isoprenyl diphosphate synthase sequence show ed no enzyme activity (top panel).

Wang KC, Ohnuma S (2000) Isoprenyl diphosphate synthases. Bioehim Biophys Acta 1529 33 8... 

One frugal beetle has figured out... S. Frick et al. Metal ions control product specificity of isoprenyl diphosphate synthases in the insect terpenoid pathway. 2013. Proc Natl AcadSci. 110(1 l),p.4194. DOl 10.1073/pnas.l221489110. 

Wang, K., and Ohnuma, S. (1999) Chain-length determination mechanism of isoprenyl diphosphate synthases and implications for molecular evolution. Trends Biochem. Sci. 24, 445 51... 

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