Figure 1. The electron transport chain of oxygenic photosynthesis.

Formation of the transmembrane proton electrochemical gradient coupled to the electron transport extending from H₂O oxidation to NADP⁺ reduction, in which H⁺ is translocated in the protein complexes of the PSII reaction center and cytochrome b₆f; this H⁺ gradient is utilized for ATP synthesis by the ATP synthase. PDB accession for structure data: Cyt b₆f (PDB ID 2E74), Fd (PDB ID 1EWY), ferredoxin; FNR (PDB ID 1EWY), ferredoxin- NADP⁺-reductase; PC (PDB ID 2Q5B), plastocyanin; PSII (PDB ID 3ARC) and PSI (PDB ID 1JB0), reaction center complexes.