Incorporation of [2,3-13C2]- and [2,4-13C 2]-D-1-deoxyxululose into ubiquinone of Escherichia coli via the mevalonate-independent pathway for isoprenoid biosynthesis

Abstract

[2,3-13C2]- and [2,4-13C2]-d-1-deoxyxylulose were synthesized from [2-13C]pyruvate and [1-13C]- or [2-13C]-dl-glyceraldehyde using the enzyme d-1-deoxyxylulose 5-phosphate synthase from Escherichia coli which was overexpressed in this bacterium. These doubly-labeled isoprenoid precursors in the mevalonate independent route were incorporated into the ubiquinone of E. coli. 1J 13C/13C coupling constants were respectively found in isoprenic units between carbon atoms derived 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 isoprenoids and confirming that the branched isoprenic skeleton resulted from a rearrangement of the straight chain from carbohydrate precursor. © 1997 Elsevier Science Ltd. All rights reserved.