engleski

Revisiting standard model of electron transport in photosynthesis

Ferredoxin-NADP+ oxidoreductase (FNR) catalyzes the last step of photosynthetic electron transfer from ferredoxin (FD) to NADP+. Recently we have proposed that the dynamic recruitment of FNR to the integral thylakoid membrane protein rhodanase-like protein TROL can function as an alternating switch that can rapidly partition electrons between various Fd/FNR-dependent pathways. By using electron paramagnetic resonance, we have demonstrated that isolated Arabidopsis chloroplasts lacking TROL can efficiently avoid superoxide anion formation and that this mechanism is more rapid than the methyl viologen-dependent propagation of the same ROS. Further, we have shown that the dynamic recruitment of FNR to thylakoid membranes is solely TROL-dependent. We have proposed that without TROL electrons downstream of photosystem I flow more rapidly to this alternative pathway than to the FNR-dependent NADPH synthesis. Thus, we conclude that the last step of photosynthetic electron conversion, from Fd over FNR to NADPH, is not the most preferential pathway in vascular plant photosynthesis.

ferredoxin:NADP+ oxidoreductase ; photosynthetic electron transport, Photosystem I ; ROS ; electron paramagnetic resonance

nije evidentirano