at the University of Cambridge in England, who was not involved in the studies. “To replace it we need to source those electrons, and water is the best source.”Photosynthesis uses sunlight to convert carbon dioxide and water into sugar, releasing oxygen as a waste product.at the Free University of Berlin in Germany, a co-author on one of the new studies, because it “led to the oxygen-rich atmosphere we have today on Earth.
The water molecules are split by a large enzyme—a protein structure that acts as a catalyst, speeding up biochemical reactions—called Photosystem II. Its name is a historical accident: It acts first in the process of photosynthesis, but another enzyme that comes later was discovered first. It’s not clear what these intermediate steps are. Two water molecules may be temporarily transformed into a peroxide, in which their oxygens are joined by a new bond, forcing the hydrogens to be removed.
These data also suggests that there is an intermediate step in the water-splitting reaction. Dau’s team also found that the reaction was only possible because one electron and four protons moved in a coordinated way, revealing that Photosystem II exerts precise control over even the smallest particles in the reaction.“resolved the final step of this catalysis pathway,” Zhang says. “It has been one of the biggest questions in the field.