Methylerythritol

Rodriguez-Concepcion, M. and Boronat, A., Elncidation of the methylerythritol phosphate pathway for isoprenoid biosynthesis in hacteria and plastids a metabolic milestone achieved throngh genomics. Plant Physiol. 130, 1079, 2002. Rodriguez-Concepcion, M., Early steps in isoprenoid biosynthesis multilevel regulation of the supply of common precursors in plant cells, Phytochem. Rev. 5, 1, 2006. Eisenreich, W., Rohdich, F., and Bacher, A., Deoxyxylulose phosphate pathway to terpenoids, Trends Plant Sci. 6, 78, 2001. 

Hampel, D., Mosandl, A., and Wust, M., Biosynthesis of mono- and sesquiterpenes in carrot roots and leaves (Daucus carota L.) metabolic cross talk of cytosolic mevalonate and plastidial methylerythritol phosphate pathways, Phytochemistry 66, 305, 2005. 

Walter, M.H., Fester, T., and Strack, D., Arbuscular mycorrhizal fungi induce the non-mevalonate methylerythritol phosphate pathway of isoprenoid biosynthesis correlated with accumulation of the yellow pigment and other apocarotenoids. Plant J. 21, 571, 2000. 

Walter, M. H., D. S. Flo et al. (2007). Apocarotenoid biosynthesis in arbuscular mycorrhizal roots Contributions from methylerythritol phosphate pathway isogenes and tools for its manipulation. 

Rohdich, F., Wungsintaweekul, J., Fellermeier, M. et al. (1999) Cytidine 5 -triphosphate-dependent biosynthesis of isoprenoids YgbP protein of Escherichia coli catalyzes the formation of 4-diphosphocy-tidyl-2-C-methylerythritol. Proceedings of the National Academy of Sciences of the United States of America, 96, 11758-11763. 

Plant metabolism can be separated into primary pathways that are found in all cells and deal with manipulating a uniform group of basic compounds, and secondary pathways that occur in specialized cells and produce a wide variety of unique compounds. The primary pathways deal with the metabolism of carbohydrates, lipids, proteins, and nucleic acids and act through the many-step reactions of glycolysis, the tricarboxylic acid cycle, the pentose phosphate shunt, and lipid, protein, and nucleic acid biosynthesis. In contrast, the secondary metabolites (e.g., terpenes, alkaloids, phenylpropanoids, lignin, flavonoids, coumarins, and related compounds) are produced by the shikimic, malonic, and mevalonic acid pathways, and the methylerythritol phosphate pathway (Fig. 3.1). This chapter concentrates on the synthesis and metabolism of phenolic compounds and on how the activities of these pathways and the compounds produced affect product quality. 

Rohmer M (2007) Diversity in isoprene unit biosynthesis the methylerythritol phosphate pathway in bacteria and plastids. Pure Appl Chem 79 739-751... 

Cvejic JH, Rohmer M (2000) C02 as main carbon source for isoprenoid biosynthesis via the mevalonate-independent methylerythritol 4-phosphate route in the marine diatoms Phaeodactylum tricomutum and Nitzschia ovalis. Phytochemistry 53 21-28 de Nys R, Steinberg PD, Willemsen P, Dworjanyn SA, Gabelish CL, King RJ (1995) Broad-spectrum effects of secondary metabolites from the red alga Delisea pulchra in antifouling assays. Biofouling 8 259-271... 

Keeling PJ, Burger G, Dumford DG, Lang BF, Lee RW, Pearlman RE, Roger AJ, Gray MW (2005) The tree of eukaryotes. Trends Ecol Evol 20 670-676 Kim D, Filtz MR, Proteau PJ (2004) The methylerythritol phosphate pathway contributes to carotenoid but not phytol biosynthesis in Euglena gracilis. J Nat Prod 67 1067-1069... 

Schoenwaelder MEA (2002) Physode distribution and the effect of thallus sunburn in Flormosira banksii (Fucales, Phaeophyceae). Bot Mar 45 262-266 Schoenwaelder MEA, Clayton MN (2000) Physode formation in embryos of Phyllospora comosa and Flormosira banksii (Phaeophyceae). Phycologia 39 1-9 Schwender J, Gemunden C, Lichtenthaler HK (2001) Chlorophyta exclusively use the 1-deoxyxylulose 5-phosphate/2-C-methylerythritol 4-phosphate pathway for the biosynthesis of isoprenoids. Planta 212 416 123... 

Colonization of barley, wheat and maize and rice roots by Glomus intraradices resulted in strong induction of transcript levels of the pivotal enzymes of methylerythritol phosphate pathway of isoprenoid biosynthes i.e., 1 -deoxy-D-xylulose 5-phosphate synthase (DXS) and 1 -deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) (Walter et al., 2000). At the same time six cyclohexenone derivatives were characterized from mycorrhizal wheat and maize roots. DXS2 transcript levels are low in most tissues but are strongly stimulated in roots upon colonization by mycorrhizal fungi, correlated with accumulation of carotenoids and apocarotenoids (Walter et al., 2002). Some reports show that the AM symbiosis may cause an increase, decrease, or no change in the plant defense reactions (Guenoune et al., 2001 Mohr et al., 1998). 

DMAPP, a prenyl-donor substrate in cytokinin biosynthesis, is an intermediate of both the methylerythritol phosphate (MEP) and mevalonate (MVA) pathways, whereas HMBDP, another substrate of Agrobacterium IPTs, is synthesized via only the MEP pathway. In general, the MEP pathway is found in bacteria and plastids, and the MVA pathway is found in the cytosol of eukaryotes.413-415... 

Keywords biosynthesis genes monoterpenes sesquiterpenes diterpenes mevalonate pathway methylerythritol phosphate pathway... 

Rohmer, M. (2008) From molecular fossils of bacterial hopanoids to the formation of isoprene units discovery and elucidation of the methylerythritol phosphate pathway. Lipids, 43,1095-107. 

Methylerythritol Phosphate Pathway for the Formation of Isoprene Units... 

The biologic precursors of isoprene units are isopentenyl diphosphate 7 (IPP) and dimethylallyl diphosphate 8 (DMAPP). These precursors can be obtained by two different metabolic pathways the mevalonate (MVA) pathway (Fig. 1), which was the first one to be elucidated, and the long-overlooked methylerythritol phosphate (MEP) pathway (Fig. 3) (1, 2). 

Figure 2 Methylerythritol phosphate 12 pathway for the biosynthesis of isopentenyl diphosphate 7 and dimethylallyl diphosphate 8.

Incorporation of H-labeled deoxyxylulose and methylerythritol into terpenoids from bacteria and from plant plastids... 

Free methylerythritol is a widespread polyol in plants. The formation of the isoprene skeleton via the alternative route involves an intramolecular rearrangement. The branched carbon skeleton of ME can be deduced from the rearrangement of the straight chain DX (Fig. 4). Deuterium-labeled ME isotopomers were synthesized chemically and were incorporated into the prenyl chains of the E. coli quinones (2). 

Seemann M, Rohmer M. Isoprenoid biosynthesis via the methylerythritol phosphate pathway GcpE and LytB, two novel iron/ sulphur proteins. C.R. Chimie 2007. In press. 

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