engleski

Studying dual localization of a protein that influences the fate of photosynthetic electrons

The transport of photosynthetic electrons terminates at the stromal side of photosystem I, where they are being handed over from ferredoxin (Fd) to ferredoxin:NADPH oxydoreductase (FNR) or other stromal acceptors, depending on the organelle needs. The key regulator of this final electron transfer step is thylakoid-membrane incorporated protein TROL (thylakoid rhodanase-like) that interacts with FNR by dynamic tethering and therefore influences the destination of photosynthetically-derived electrons. The absence of TROL impairs linear electron flow and increases NPQ, while the distribution of high-energy electrons is directed towards the ROS detoxification pathways rather than to the NADP+ reduction (Calvin cycle). Trol plants showed increased stress resistance along with significantly enhanced ROS detoxification. Also, the absence of TROL leads to the complete loss of the dynamicity of the FNR-binding and release to/from the thylakoid membrane. TROL has dual localization in chloroplasts: in the inner envelope membrane as a precursor of 70 kDa, and in the thylakoid membranes in its 66 kDa mature form. Its role in the inner envelope has not been researched yet. In an attempt to better understand the properties of this protein, targeted deletions around the presequence processing site have been made. Single exchange of Ala67 to Ile67 showed to interfere with TROL processing, with resulting incorporation at the single location in the inner envelope membrane. Engineering the Arabidopsis mutant plants, containing TROL protein just in the inner envelope, might further reveal its roles in photosynthesis regulation and its yet unknown function in the envelope membrane.

TROL ; FNR ; thylakoids ; inner envelope ; protein import ; thermolysin ; photosynthesis

nije evidentirano