Contribution of the mevalonate and methylerythritol phosphate pathways to the biosynthesis of dolichols in plants.
Plant isoprenoids are derived from two biosynthetic pathways, the cytoplasmic mevalonate (MVA) and the plastidial methylerythritol phosphate (MEP) pathway. In this study their respective contributions toward formation of dolichols in Coluria geoides hairy root culture were estimated using in vivo labeling with (13)C-labeled glucose as a general precursor. NMR and mass spectrometry showed that both the MVA and MEP pathways were the sources of isopentenyl diphosphate incorporated into polyisoprenoid chains. The involvement of the MEP pathway was found to be substantial at the initiation stage of dolichol chain synthesis, but it was virtually nil at the terminal steps; statistically, 6-8 isoprene units within the dolichol molecule (i.e. 40-50% of the total) were derived from the MEP pathway. These results were further verified by incorporation of [5-(2)H]mevalonate or [5,5-(2)H(2)]deoxyxylulose into dolichols as well as by the observed decreased accumulation of dolichols upon treatment with mevinolin or fosmidomycin, selective inhibitors of either pathway. The presented data indicate that the synthesis of dolichols in C. geoides roots involves a continuous exchange of intermediates between the MVA and MEP pathways. According to our model, oligoprenyl diphosphate chains of a length not exceeding 13 isoprene units are synthesized in plastids from isopentenyl diphosphate derived from both the MEP and MVA pathways, and then are completed in the cytoplasm with several units derived solely from the MVA pathway. This study also illustrates an innovative application of mass spectrometry for qualitative and quantitative evaluation of the contribution of individual metabolic pathways to the biosynthesis of natural products.
Skorupinska-Tudek
Karolina
K
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland.
Poznanski
Jaroslaw
J
Wojcik
Jacek
J
Bienkowski
Tomasz
T
Szostkiewicz
Izabela
I
Zelman-Femiak
Monika
M
Bajda
Agnieszka
A
Chojnacki
Tadeusz
T
Olszowska
Olga
O
Grunler
Jacob
J
Meyer
Odile
O
Rohmer
Michel
M
Danikiewicz
Witold
W
Swiezewska
Ewa
E
D000438:Alcohols / Q000737:chemistry; D003593:Cytoplasm / Q000378:metabolism; D004286:Dolichols / Q000737:chemistry*; D004896:Erythritol / Q000031:analogs & derivatives* / Q000378:metabolism; D005947:Glucose / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry / Q000379:methods; D008798:Mevalonic Acid / Q000378:metabolism*; D008954:Models, Biological; D018517:Plant Roots / Q000378:metabolism; D010944:Plants / Q000378:metabolism*; D018087:Plastids / Q000737:chemistry / Q000378:metabolism; D011336:Probability; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013261:Sterols / Q000737:chemistry; D013403:Sugar Phosphates / Q000378:metabolism*
C114232:2-C-methylerythritol 4-phosphate; D000438:Alcohols; D004286:Dolichols; D013261:Sterols; D013403:Sugar Phosphates; D005947:Glucose; D004896:Erythritol; D008798:Mevalonic Acid