Photosystem II
Photosystem II is a large protein complex. It is the first protein complex in the light-dependent reactions of oxygenic photosynthesis.
The complex is in the thylakoid membrane of plants, algae, and cyanobacteria.
In the photosystem, enzymes capture photons of light to energize electrons. The electrons are then transferred by coenzymes and cofactors. The energized electrons are replaced by oxidizing water to form hydrogen ions and molecular oxygen.
By replenishing lost electrons with electrons from the splitting of water, photosystem II provides the electrons for photosynthesis to occur.[1]
Photosystem II Media
Cyanobacterial photosystem II, Monomer, PDB 2AXT.
Schematic of PSII, highlighting electron transfer.
Proposed structure of Manganese Center
Water-splitting process: Electron transport and regulation. The first level (A) shows the original Kok model of the S-states cycling, the second level (B) shows the link between the electron transport (S-states advancement) and the relaxation process of the intermediate S-states ([YzSn], n=0,1,2,3) formation
References
- ↑ Nowicka, Beatrycze & Kruk, Jerzy 2010. Occurrence, biosynthesis and function of isoprenoid quinones. Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1797 (9): 1587–1605.