Biosynthesis of Terpenoids: 4-Diphosphocytidyl-2-C-methyl-D-erythritol Kinase from Tomato

The putative catalytic domain (residues 81-401) of a predicted tomato protein with similarity to 4-diphosphocytidyl-2-C-methyl-D-erythritol kinase of Escherichia coli was expressed in a recombinant E. coli strain. The protein was purified to homogeneity and was shown to catalyze the phosphorylation of the position 2 hydroxy group of 4-diphosphocytidyl-2-C-methyl-D-erythritol at a rate of 33 μ mol· mg-1· min-1. The structure of the reaction product, 4-diphosphocytidyl-2-C-methyl-D-erythritol 2-phosphate, was established by NMR spectroscopy. Divalent metal ions, preferably Mg2+, are required for activity. Neither the tomato enzyme nor the E. coli ortholog catalyzes the phosphorylation of isopentenyl monophosphate.