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Publication Abstract from PubMed

Photosystem I (PSI), a large protein complex located in the thylakoid membrane, mediates the final step in light-driven electron transfer to the stromal electron carrier protein ferredoxin (Fd). Here, we report the first structural description of the PSI-Fd complex from Thermosynechococcus elongatus. The trimeric PSI complex binds three Fds in a non-equivalent manner. While each is recognized by a PSI protomer in a similar orientation, the distances between Fds and the PSI redox centres differ. Fd binding thus entails loss of the exact three-fold symmetry of the PSI's soluble subunits, inducing structural perturbations which are transferred to the lumen through PsaF. Affinity chromatography and nuclear magnetic resonance analyses of PSI-Fd complexes support the existence of two different Fd-binding states, with one Fd being more tightly bound than the others. We propose a dynamic structural basis for productive complex formation, which supports fast electron transfer between PSI and Fd.

X-ray structure of an asymmetrical trimeric ferredoxin-photosystem I complex.,Kubota-Kawai H, Mutoh R, Shinmura K, Setif P, Nowaczyk MM, Rogner M, Ikegami T, Tanaka H, Kurisu G Nat Plants. 2018 Apr;4(4):218-224. doi: 10.1038/s41477-018-0130-0. Epub 2018 Apr , 2. PMID:29610537^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.