TITLE

Isoprenoid biosynthesis in chloroplasts via the methylerythritol phosphate pathway: the (E)-4-hydroxy-3-methylbut-2-enyl diphosphate synthase (GcpE) fromArabidopsis thalianais a [4Fe-4S] protein

AUTHOR(S)
Seemann, Myriam; Wegner, Patrick; Sch�nemann, Volker; Bui, Bernadette; Wolff, Murielle; Marquet, Andr�e; Trautwein, Alfred; Rohmer, Michel
PUB. DATE
March 2005
SOURCE
Journal of Biological Inorganic Chemistry;Mar2005, Vol. 10 Issue 2, p131
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The mevalonate-independent methylerythritol phosphate pathway is widespread in bacteria. It is also present in the chloroplasts of all phototrophic organisms. Whereas the first steps, are rather well known, GcpE and LytB, the enzymes catalyzing the last two steps have been much less investigated. 2-C-Methyl-D-erythritol 2,4-cyclodiphosphate is transformed by GcpE into 4-hydroxy-3-methylbut-2-enyl diphosphate, which is converted by LytB into isopentenyl diphosphate or dimethylallyl diphosphate. Only the bacterial GcpE and LytB enzymes have been investigated to some extent, but nothing is known about the corresponding plant enzymes. In this contribution, the prosthetic group of GcpE from the plantArabidopsis thalianaand the bacteriumEscherichia colihas been fully characterized by M�ssbauer spectroscopy after reconstitution with57FeCl3, Na2S and dithiothreitol. It corresponds to a [4Fe-4S] cluster, suggesting that both plant and bacterial enzymes catalyze the reduction of 2-C-methyl-D-erythritol 2,4-cyclodiphosphate into (E)-4-hydroxy-3-methylbut-2-enyl diphosphate via two consecutive one-electron transfers. In contrast to the bacterial enzyme, which utilizes NADPH/flavodoxin/flavodoxin reductase as a reducing shuttle system, the plant enzyme could not use this reduction system. Enzymatic activity was only detected in the presence of the 5-deazaflavin semiquinone radical.
ACCESSION #
16675165

 

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