Isoprenoid biosynthesis in plant chloroplasts via the MEP pathway: direct thylakoid/ferredoxin-dependent photoreduction of GcpE/IspG.
In the methylerythritol phosphate pathway for isoprenoid biosynthesis, the GcpE/IspG enzyme catalyzes the conversion of 2-C-methyl-d-erythritol 2,4-cyclodiphosphate into (E)-4-hydroxy-3-methylbut-2-enyl diphosphate. This reaction requires a double one-electron transfer involving a [4Fe-4S] cluster. A thylakoid preparation from spinach chloroplasts was capable in the presence of light to act as sole electron donor for the plant GcpE Arabidopsis thaliana in the absence of any pyridine nucleotide. This is in sharp contrast with the bacterial Escherichia coli GcpE, which requires flavodoxin/flavodoxin reductase and NADPH as reducing system and represents the first proof that the electron flow from photosynthesis can directly act in phototrophic organisms as reducer in the 2-C-methyl-d-erythritol 4-phosphate pathway, most probably via ferredoxin, in the absence of any reducing cofactor. In the dark, the plant GcpE catalysis requires in addition of ferredoxin NADP(+)/ferredoxin oxido-reductase and NADPH as electron shuttle.
Université Louis Pasteur/CNRS, Institut de Chimie LC3/UMR 7177, 4 rue Blaise Pascal, 67070 Strasbourg Cedex, France.
Myriam
M
Seemann
Bernadette
B
Tse Sum Bui
Murielle
M
Wolff
Myroslawa
M
Miginiac-Maslow
Michel
M
Rohmer
D019883:Alkyl and Aryl Transferases / Q000378:metabolism; D017360:Arabidopsis / Q000201:enzymology; D029681:Arabidopsis Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004579:Electron Transport; D004896:Erythritol / Q000031:analogs & derivatives / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D005288:Ferredoxins / Q000378:metabolism*; D008027:Light; D010084:Oxidation-Reduction; D010088:Oxidoreductases; D010788:Photosynthesis; D018724:Spinacia oleracea / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects; D013729:Terpenes / Q000378:metabolism*; D020524:Thylakoids / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects
D029681:Arabidopsis Proteins; D005288:Ferredoxins; D013729:Terpenes; C443879:methyl-D-erythritol 2,4-cyclodiphosphate; D010088:Oxidoreductases; C000708271:AT5G60600 protein, Arabidopsis; D019883:Alkyl and Aryl Transferases; D004896:Erythritol