Toward Elucidation of the Photosynthetic Electron Transfer Mechanism

Ferredoxins (Fds) are iron–sulfur proteins found in various organisms, and they act as multifunctional electron carriers in diverse redox systems. In plants, numerous Fd-dependent enzymes such as dark-operative protochlorophyllide reductase (DPOR), glutamate synthase (Fd-GOGAT), sulfite reductase (SiR), FTR (ferredoxin-thioredoxin reductase), and ferredoxin:NADP+ reductase (FNR) exist. However, there are no consensus sequences for Fd dependence, which is why we are interested in the molecular interaction between Fd and Fd-interacting proteins, including Photosystem I. The efficient electron transfer and backflow prevention mechanisms by Fd are also very interesting. Ultrahigh-resolution X-ray structure analysis by low-dose data collection will greatly advance our understanding of the electron transfer mechanism by Fd.