Structural and functional characterization of ferredoxin-NADP(+)-oxidoreductase using knock-out mutants of Arabidopsis

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


Interna författare/redaktörer


Publikationens författare: Lintala M, Allahverdiyeva Y, Kidron H, Piippo M, Battchikova N, Suorsa M, Rintamäki E, Salminen TA, Aro EM, Mulo P
Förläggare: WILEY-BLACKWELL
Publiceringsår: 2007
Tidskrift: Plant Journal
Tidskriftsakronym: PLANT J
Volym: 49
Nummer: 6
Artikelns första sida, sidnummer: 1041
Artikelns sista sida, sidnummer: 1052
Antal sidor: 12
ISSN: 0960-7412
eISSN: 1365-313X


Abstrakt

In Arabidopsis thaliana, the chloroplast-targeted enzyme ferredoxin-NADP(+)-oxidoreductase (FNR) exists as two isoforms, AtLFNR1 and AtLFNR2, encoded by the genes At5g66190 and At1g20020, respectively. Both isoforms are evenly distributed between the thylakoids and soluble stroma, and they are separated by two-dimensional electrophoresis in four distinct spots, suggesting post-translational modification of both isoforms. To reveal the functional specificity of AtLFNR1, we have characterized the T-DNA insertion mutants with an interrupted At5g66190 gene. Absence of AtLFNR1 resulted in a reduced size of the rosette with pale green leaves, which was accompanied by a low content of chlorophyll and light-harvesting complex proteins. Also the photosystem I/photosystem II (PSI/PSII) ratio was significantly lower in the mutant, but the PSII activity, measured as the F-V/F-M ratio, remained nearly unchanged and the excitation pressure of PSII was lower in the mutants than in the wild type. A slow re-reduction rate of P700 measured in the mutant plants suggested that AtLFNR1 is involved in PSI-dependent cyclic electron flow. Impaired function of FNR also resulted in decreased capacity for carbon fixation, whereas nitrogen metabolism was upregulated. In the absence of AtLFNR1, we found AtLFNR2 exclusively in the stroma, suggesting that AtLFNR1 is required for membrane attachment of FNR. Structural modeling supports the formation of a AtLFNR1-AtLFNR2 heterodimer that would mediate the membrane attachment of AtLFNR2. Dimer formation, in turn, might regulate the distribution of electrons between the cyclic and linear electron transfer pathways according to environmental cues.


Nyckelord

electron transfer, ferredoxin-NADP(+)-oxidoreductase, structural model

Senast uppdaterad 2019-22-07 vid 03:28