1-Deoxyxylulose 5-phosphate synthase

Matthews, P.D. and Wurtzel, E.T., Metabolic engineering of carotenoid accumulation in Escherichia coli by modulation of the isoprenoid precursor pool with expression of deoxyxylulose phosphate synthase, Appl. Microbiol. Biotechnol. 53, 396, 2000. 

MAHMOUD, S.S., CROTEAU, R., Metabolic engineering of essential oil yield and composition in mint by altering expression of deoxyxylulose phosphate reductoisomerase and menthofuran synthase, Proc. Natl. Acad. Sci. USA, 2001, 98, 8915-8920. 

Other ThDP enzymes catalyze the formation of C-C bonds by transferring C2 units from a donor compound to an acceptor compound (transferase activity). We have studied the E. coli transketolase with respect to structure-function relationships, as well as to possible applications in asymmetric syntheses (Section 2.2.2.2.1). During the late 1990s a transketolase-like enzyme, 1-deoxyxylulose 5-phosphate synthase, was discovered. Its structure and value in chemoenzymatic syntheses were also assessed in project B21 (Section 2.2.2.2.2). 

Fig. 3. Biosynthesis of TIAs in C. roseus. Solid arrows indicate single enzymatic conversions, whereas dashed arrows indicate multiple enzymatic conversions. AS Anthranilate synthase, DXS D-l-deoxyxylulose 5-phosphate synthase G10H geraniol 10-hydroxylase CPR cytochrome P450 reductase TDC tryptophan decarboxylase STR strictosidine synthase SGD strictosidine /1-D-glucosidase D4H desacetoxyvindoline 4-hydroxylase DAT acetyl-CoA 4-O-deacetylvindoline 4-O-acetyl transferase. Genes regulated by ORCA3 are underlined. Reprinted with permission from [91]. Copyright (2000) American Association for the Advancement of Science...

Figure 3 Formation of deoxyxylulose phosphate 11 (DXP) from pyruvate 9 and glyceraidehyde phosphate 10 by the DXP synthase.

In bacteria and plastids of plants, formation of prenyl pyrophosphates, which are the precursors of carotenoids, proceeds via an alternative—the glyceraldehyde-3-phosphate pyruvate pathway. The pathway is apparently the sole source of isoprenoid compounds for the unicellular algae Scenedesmus (Metzler 2003). Initially, pyruvate is decarboxylated by a l-deoxyxylulose-5-phosphate synthase and condensed with D-glyceraldehyde 3-phosphate to form 1-deoxyxylulose 5-phosphate. This product may be the branching point for independent routes to isopentyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). 

ESTEVEZ, J. M., CANTERO, A., ROMERO, C., KAWAIDE, H., JIMENEZ, L, F., KUZUYAMA, T., SETO, H., KAMIYA, Y., LEON, P., Analysis of the expression of CLAl, a gene that encodes the 1- deoxyxylulose 5-phosphate synthase of the 2-C-methyl-D-erythritol-4- phosphate pathway in Arabidopsis., Plant Physiol. 2000,124, 95-104. 

Note DXR, Deoxyxylulose phosphate reductoisomerase 1-3-h, limonene-3-hydroxylase MFS, menthofuran synthase WT, wild type. 

Sprenger, G.A. et al.. Identification of a thiamin-dependent synthase in Escherichia coli required for the formation of the 1-deoxy-D-xylulose 5-phosphate precursor to isoprenoids, thiamin, and pyridoxol, Proc. Natl. Acad Sci. USA 94, 12857, 1997. Lange, B.M. et al., A family of transketolases that directs isoprenoid biosynthesis via a mevalonate-independent pathway, Proc. Natl. Acad Sci. USA 95, 2100, 1998. Lois, L.M. et al., Cloning and characterization of a gene from Escherichia coli encoding a transketolase-like enzyme that catalyzes the synthesis of D-1- deoxyxylulose 5-phosphate, a common precursor for isoprenoid, thiamin, and pyridoxol biosynthesis, Proc. Natl. Acad. Sci. USA 95, 2105, 1998. 

Despite the importance of pyridoxal phosphate (PLP) in cellular metabolism, the pathways by which this cofactor is synthesized have been characterized relatively recentlyTwo mutually exclusive pathways have been described, with eubacteria using deoxyxylulose-5-phosphate (DXP) as a key intermediate (Scheme 20). More recent work has identified a second, DXP-independent pathway (Scheme 21), which appears to be used by a wide range of organisms and is distinguished by the involvement ofPLP synthase. In B. subtilis, fungi,Plasmodium falciparum and plants, this enzyme is a heterodimer composed of two subunits encoded... 

FIGURE 523 The leaf isoprene formation at subcellular compartment level based on Reference [11].This figure illustrates the role of the cytosolic mevalonate and chloroplastic deoxyxylulose-5-phosphate (DOXP) pathways in the formation of dimethylallyl diphosphate (DMAPP), the precursor of isoprene by the isoprene synthase reaction. IPP, isopentenyl diphosphate HMG-CoA, 3-hydroxy-3-methylglutaryl-coen-zyme A MEP, 2-C-methyl-D-erythritol 4-phosphate PEP, phosphoenolpyruvate. (Adapted and reprinted with kind permission from Springer Science + Business Media [16], figure 1.)... 

Fig. 95.1 Terpene biosynthesis pathways and their subcellular localization in the plants. Different classes of terpenes are respectively formed in the cytosol or the plastid by two independent pathways in the plants, that is, acetate-mevalonate pathway (MEV) (cytosol) and methylerythritol 4-phosphate (MEP) or deoxyxylulose 5-phosphate pathway (DXP) (plastid). Mraioterpcmes, diterpenes, and tetraterpenes are derived from IPP and DMAPP Irran the plastidial MEP ot DXP pathway. Sesquiterpenes and triterpenes are biosynthesized from IPP and DMAPP from the cytosol pathway. Black square with a white question mark suggests a possible transport of IPP (isopentenylpyrophosphate) from the plastid to the cytosol. Other metabolites involved in the different steps are DMAPP dimethylallylpyrophosphate, FPP famesylpyrophosphate, GASP D- glyceraldehyde- 3-phosphate, GPP geranylpyrophosphate, GGPP geranylgeranylpyro-phosphate. TPSs in the circle correspond to terpene synthases. Broken arrows show several enzymatic steps (Adapted from Aharoni et al. [8] and Sallaud et al. [154])...

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