An international team of scientists is getting closer to the answer thanks to unprecedented, atomic-scale images of a protein complex found in plants, algae, and cyanobacteria captured by ultrafast X-ray lasers.
The experiments, led by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), are helping researchers narrow down the process by which the protein, called photosystem II, uses light energy to split water and create oxygen. Nearly all the oxygen in the atmosphere is produced in this system. Just as importantly, this reaction also yields protons and electrons that are used to reduce carbon dioxide to carbohydrates later in the photosynthesis cycle.