Redox regulation of chloroplastic glucose-6-phosphate dehydrogenase: a new role for f-type thioredoxin.
Glucose-6-phosphate dehydrogenase (G6PDH) is the key enzyme of the oxidative pentose phosphate pathway supplying reducing power (as NADPH) in non-photosynthesizing cells. We have examined in detail the redox regulation of the plastidial isoform predominantly present in Arabidopsis green tissues (AtG6PDH1) and found that its oxidative activation is strictly dependent on plastidial thioredoxins (Trxs) that show differential efficiencies. Light/dark modulation of AtG6PDH1 was reproduced in vitro in a reconstituted ferredoxin/Trx system using f-type Trx allowing to propose a new function for this Trx isoform co-ordinating both reductive (Calvin cycle) and oxidative pentose phosphate pathways.
Née
Guillaume
G
Institut de Biotechnologie des Plantes, UMR 8618 CNRS/Université Paris-Sud, Orsay, France.
Zaffagnini
Mirko
M
Trost
Paolo
P
Issakidis-Bourguet
Emmanuelle
E
D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054479:Chloroplast Thioredoxins / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000201:enzymology*; D003545:Cysteine / Q000378:metabolism; D003624:Darkness; D005288:Ferredoxins / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008027:Light; D008958:Models, Molecular; D010084:Oxidation-Reduction; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D054479:Chloroplast Thioredoxins; D005288:Ferredoxins; D007527:Isoenzymes; D011994:Recombinant Proteins; D005954:Glucosephosphate Dehydrogenase; D003545:Cysteine