Photosynthetic oxygen formation

Plants produce the atmospheric dioxygen from water – powered by sunlight and catalysed at a manganese complex in a protein called photosystem II. To learn more about this photosynthetic water oxidation, researchers sent laser flashes on photosystem II. They recorded X-ray fluorescence on a time scale of 10 microseconds to find out how different oxidation states of the manganese complex develop.

Extended scheme of the reaction cycle of photosynthetic water oxidation. A new intermediate state (S4) – crucial in O₂ production – has been identified (Image credit: M. Haumann, copyright 2005 M. Haumann).

Further information:

• Photosynthetic dioxygen formation tracked by X-ray experiments with microsecond resolution

• Ref.: M. Haumann et al., Science 310, 1019-1021 (2005).