engleski

Regulation of the electron transfer at chloroplast membranes – what happens when the dual localization of TROL protein converts to the single?

Thylakoid rhodanese-like protein (TROL), a photosynthetic membrane component, is a hub at the end of the photosynthetic electron transfer chain that in vascular plants influences the preferential electron transfer catalyzed by the enzyme ferredoxin:NADPH oxidoreductase (FNR) for the production of sugars. Investigation of TROL knock-out mutants unraveled its property in the dynamic binding of FNR, with this interaction being a switch influencing photosynthetic electron destination sinks, according to the organelle needs. Rhodanese domain of the TROL has been shown as essential for this interaction. By monitoring ROS formation and subsequent induction of plant stress-relief responses we clearly demonstrated that plants devoid of TROL cope better with oxidative stress by fast elimination of reactive oxygen species. This property is currently being investigated into more detail since these plants are potential candidates more resilient plants of the world with aggravated environmental stresses. TROL is localized in the thylakoids, in its mature form, where it participates in the regulation of photosynthetic electron utilization, and in the inner envelope (IE) of chloroplasts, in its precursor form, where its function is so far unknown. Whether it represents just a storage protein for FNR or is involved in redox sensing and/or in protein import, remains to be resolved. For this purpose, by using the presequence directed mutagenesis and in vitro protein import experiments, we managed to arrest TROL at a single location inside the chloroplasts – in the IE membrane. We then engineered Arabidopsis plants with the single-localized TROL. TROL-IE plants should enable investigation of its so far unknown function at the inner envelope.

TROL ; FNR ; electron sinks ; inner envelope ; thylakoids ; mutagenesis ; stress response

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