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A new concept for ferredoxin-NADP(H) oxidoreductase binding to plant thylakoids
J Philipp Benz1, Minna Lintala, Jürgen Soll
1Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany.
Trends in Plant Science
|September 21, 2010
Summary
The ferredoxin (Fd):ferredoxin-NADP(+) oxidoreductase (FNR) enzyme couple is crucial for photosynthesis. Most thylakoid-bound FNR in plants is not essential, suggesting its distribution regulates chloroplast electron flow.
Area of Science:
- Plant Biology
- Photosynthesis Research
- Biochemistry
Background:
- Photosynthesis regulation involves coupling light reactions to carbon fixation.
- The ferredoxin (Fd):ferredoxin-NADP(+) oxidoreductase (FNR) complex links membrane-bound light reactions to stromal metabolic pathways.
- Understanding FNR's localization and activity is key to photosynthetic efficiency.
Purpose of the Study:
- To re-evaluate the role and necessity of thylakoid-bound FNR in higher plants.
- To investigate the distribution of FNR between thylakoid and stromal compartments.
- To propose a regulatory function for FNR localization in chloroplast electron partitioning.
Main Methods:
- Analysis of FNR binding to thylakoids.
- Re-evaluation of existing data on FNR activity in photosynthetic reactions.
- Biochemical and physiological assessments of FNR distribution.
Main Results:
- The majority of thylakoid-bound FNR in higher plants is not required for photosynthesis.
- FNR's localization is not solely indicative of its activity in photosynthetic electron transfer.
- Chloroplast FNR distribution is proposed as a regulatory mechanism.
Conclusions:
- The current understanding of membrane-bound FNR's essential role in photosynthesis needs revision.
- FNR's partitioning between stroma and thylakoids is a critical regulatory point.
- This localization mechanism fine-tunes ferredoxin-dependent electron distribution for optimal photosynthesis.
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