DXP levels in cells expressing wild type and mutant <i>aceE</i> and <i>ribB</i> genes.

<p><i>E.coli</i> cells defective in both DXS and DXR were transformed with pCRII-TOPO constructs with the indicated wild type or mutant genes or an empty vector control (Ø). Positive transformants were grown in triplicate for 5 h with MVA, and DXP levels were measured by LC-MS. Mean and standard deviation (n = 3) values are represented relative to the levels in Ø controls.</p

Ocurrence of identified mutations in EcAB4-2 cells.

<p>Ocurrence of identified mutations in EcAB4-2 cells.</p

Biosynthesis of isoprenoid precursors in <i>E. coli</i>.

<p>The indicated genes (in italics) encode enzymes that produce the first intermediates of the MEP pathway either originally (<i>dxs</i>, <i>dxr</i>) or by mutation as indicated by asterisks (<i>aceE</i>, <i>ribB</i>). The <i>E. coli</i> strains used in this work are engineered to synthesize isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) from exogenously supplied mevalonic acid (MVA). GAP, D-glyceraldehyde 3-phosphate; DXP, 1-deoxy-D-xylulose 5-phosphate; MEP, 2-<i>C</i>-methyl-D-erythritol 4-phosphate.</p

Complementation of <i>E.coli</i> strains defective in DXS or DXR.

<p>Cells were transformed with pCRII-TOPO constructs and plated on LB medium containing chloramphenicol (for the disruption of chromosomal <i>dxs</i> or <i>dxr</i> genes), kanamycin (for the MVA operon) and ampicillin (for the introduced plasmid). The medium was supplemented (+) or not (−) with MVA as indicated. Plates were incubated at 37°C for 20 h. (A) Position of transformants harboring plasmids with the indicated wild type or mutant (asterisks) genes or an empty vector control (Ø). (B) EcAB4-2 (<i>dxs::CAT</i>) transformants. (C) EcAB4-10 (<i>dxr::CAT</i>) transformants.</p