TROL-FNR interaction reveals alternative pathways of electron partitioning in photosynthesis

Vojta, Lea; Carić, Dejana; Cesar, Vera; Antunović Dunić, Jasenka; Lepeduš, Hrvoje; Kveder, Marina; Fulgosi, Hrvoje (2015) TROL-FNR interaction reveals alternative pathways of electron partitioning in photosynthesis. Scientific Reports, 5 . 10085/1-10085/9. ISSN 2045-2322

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Official URL: http://www.nature.com/articles/srep10085

Abstract

In photosynthesis, final electron transfer from ferredoxin to NADP+ is accomplished by the flavo enzyme ferredoxin:NADP+ oxidoreductase (FNR). FNR is recruited to thylakoid membranes via integral membrane thylakoid rhodanase-like protein TROL. We address the fate of electrons downstream of photosystem I when TROL is absent. We have employed electron paramagnetic resonance (EPR) spectroscopy to study free radical formation and electron partitioning in TROL-depleted chloroplasts. DMPO was used to detect superoxide anion (O2.−) formation, while the generation of other free radicals was monitored by Tiron. Chloroplasts from trol plants pre-acclimated to different light conditions consistently exhibited diminished O2.− accumulation. Generation of other radical forms was elevated in trol chloroplasts in all tested conditions, except for the plants pre-acclimated to high-light. Remarkably, dark- and growth light-acclimated trol chloroplasts were resilient to O2.− generation induced by methyl-viologen. We propose that the dynamic binding and release of FNR from TROL can control the flow of photosynthetic electrons prior to activation of the pseudo-cyclic electron transfer pathway.

Item Type:

Article

Uncontrolled Keywords:

photosynthetic electron transport; Photosystem I; ROS; electron paramagnetic resonance

Subjects:

NATURAL SCIENCES > Mathematics

Divisions:

Division of Molecular Biology

Projects:

Project title	Project leader	Project code	Project type
Regulatory mechanisms of photosynthesis and plastid differentiation (Regulatorni mehanizmi fotosinteze i diferencijacija plastida)	Hrvoje Fulgosi	098-0982913-2838	MZOS
Molecular structure and dynamics in systems containing paramagnetic particles (Molekulska struktura i dinamika sustava s paramagnetskim česticama)	Marina Ilakovac-Kveder	098-0982915-2939	MZOS

Depositing User:

Lea Vojta

Date Deposited:

06 Jun 2016 12:47

URI:

http://fulir.irb.hr/id/eprint/2802

DOI:

10.1038/srep10085