INCORPORATION OF [2,3-C-13(2)]-D-1-DEOXYXYLULOSE AND [2,4-C-13(2)]-D-1-DEOXYXYLULOSE INTO UBIQUINONE OF ESCHERICHIA-COLI VIA THE MEVALONATE-INDEPENDENT PATHWAY FOR ISOPRENOID BIOSYNTHESIS

[2,3-C-13(2)]- and [2,4-C-13(2)]-D-1-deoxyxylulose were synthesized fr om [2-C-13]pyruvate and [1-C-13]- or [2-C-13]-DL-glyceraldehyde using the enzyme D-1-deoxyxylulose fi-phosphate synthase from Escherichia co li which was overexpressed in this bacterium. These doubly-labeled iso prenoid precursors in the mevalonate independent route were incorporat ed into the ubiquinone of E., coli. (1)J C-13/C-13 coupling constants were respectively found in isoprenic units between carbon atoms derive d from C-3 and C-4 of isopentenyl diphosphate using the former labeled precursor or between C-3 and C-2 using the latter, indicating that D- 1-deoxyxylulose was incorporated without prior degradation into isopre noids and confirming that the branched isoprenic skeleton resulted fro m a rearrangement of the straight chain from carbohydrate precursor. ( C) 1997 Elsevier Science Ltd. All rights reserved.