C-methyl-D-erythritol 2,4-cyclodiphosphate synthase

Figure 9.4 Monoterpene biosynthesis in peppermint oil gland secretory cells. The enzymes involved in this pathway are (1) 1-deoxy-D-xylulose 5-phosphate synthase, (2) 2-C-methyl-D-erythritol 4-phosphate reductoisomerase, (3) 2-C-methyl-D-erythritol 4-phosphate cytidyltransferase, (4) 4-(cytidine 5 -diphospho)-2-C-methyl-D-erythritol kinase, (5) 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase, (6) isopentenyl diphosphate isomerase, (7) geranyl diphosphate synthase, (8)...

C-methyl-D-erythritol 2,4-cyclodiphosphate synthase catalyses the conversion of 4-diphospho-cytidyl-2-C-methyl-D-erythritol 2-phosphate to 2-C-methyl-D-erythritol 2,4-cyclodiphosphate (MECDP) (Equation (7)). This reaction is part of the isoprenoid biosynthesis pathway in many plants and bacteria. The structure of the E. coli enzyme bound to Mn, cytosine monophosphate, and 2-C-methyl-D-erythritol 2,4-cyclodiphosphate has been determined. The enzyme in the crystal and probably in solution is trimeric, three monomers are packed in a circular assembly with three-fold symmetry. The active site is at the interface of two adjacent monomers all the ligands bound to the Mn + come from one monomer and a MECDP molecule. The structure of this active site is shown in Figure 29 ... 

MEP is first transformed into 4-(cytidine 5 -diphospho)-2-C-methyl-D-erythritol with the enzyme 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase (ispD, EC 2.7.7.60), followed by tire formation of 2-phospho-4-(cytidine 5 -diphospho)-2-C-methyl-D-erythritol catalyzed by the enzyme 4-diphosphocytidyl-2-C-methyl-D-erythritol kinase (ispE, EC 2.7.1.148). Later, the enzyme 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase (ispF, EC 4.6.1.12) produces 2-(3-methyl-D-erythritol 2,4-cyclodiphosphate, which is converted into... 

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