NADPH-dependent thioredoxin reductase and 2-Cys peroxiredoxins are needed for the protection of Mg-protoporphyrin monomethyl ester cyclase.
The chloroplast-localized NADPH-dependent thioredoxin reductase (NTRC) has been found to be able to reduce hydrogen peroxide scavenging 2-Cys peroxiredoxins. We show that the Arabidopsis ntrc mutant is perturbed in chlorophyll biosynthesis and accumulate intermediates preceding protochlorophyllide formation. A specific involvement of NTRC during biosynthesis of protochlorophyllide is indicated from in vitro aerobic cyclase assays in which the conversion of Mg-protoporhyrin monomethyl ester into protochlorophyllide is stimulated by addition of the NTRC/2-Cys peroxiredoxin system. These findings support the hypothesis that this NADPH-dependent hydrogen peroxide scavenging system is particularly important during periods with limited reducing power from photosynthesis, e.g. under chloroplast biogenesis.
Stenbaek
Anne
A
VKR Research Centre Pro-Active Plants, Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
Hansson
Andreas
A
Wulff
Ragna Peterson
RP
Hansson
Mats
M
Dietz
Karl-Josef
KJ
Jensen
Poul Erik
PE
D000332:Aerobiosis; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002734:Chlorophyll / Q000096:biosynthesis* / Q000235:genetics; D010105:Oxygenases / Q000378:metabolism*; D054464:Peroxiredoxins / Q000378:metabolism*; D013880:Thioredoxin-Disulfide Reductase / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D002734:Chlorophyll; D054464:Peroxiredoxins; D010105:Oxygenases; C053161:magnesium protoporphyrin monomethyl ester oxidative cyclase; C000612940:NTRC protein, Arabidopsis; D013880:Thioredoxin-Disulfide Reductase