A Yale-led team of chemists has unveiled the blueprints for a key enzyme that may contain design principles for a new generation of synthetic solar fuel catalysts.
The research, led by Yale’s Gary Brudvig and Christopher Gisriel, uses cryo-electron microscopy on a microorganism called Synechocystis to get an extreme close-up picture of Photosystem II, the enzyme in photosynthesis that uses water as a solar fuel, enabling researchers to observe how the enzyme works.
The study, which appears in the journal Proceedings of the National Academy of Sciences, was co-authored by researchers from the University of California-Riverside, Boston College, and City University of New York.
Photosynthesis is the mechanism by which plants and certain microorganisms, like Synechocystis, use sunlight to synthesize food from carbon dioxide and water — and fill the atmosphere with oxygen as a byproduct. At the heart of photosynthesis is Photosystem II, an enzyme that oxides water molecules, taking away their electrons to use as fuel.
Scientists have long sought ways to mimic this process to create more efficient solar fuel catalysts, by studying Photosystem II from Synechocystis. But without a clear picture of Photosystem II’s molecular structure in Synechocystis, it has been challenging for scientists to understand the results of their experiments.
Previous work led by Yale created a snapshot of Photosytem II from Synechocystis in an “immature” stage, before the enzyme was capable of water oxidation. That work allowed the researchers to better understand how the enzyme is built.
In the new study, the researchers were able to see the enzyme in Synechocystis in its mature, active form, with all of the protein subunits and activity that is present during water oxidation. The observation, made possible by cryo-electron microscopy technology at Yale’s West Campus, offers one of the closest, most detailed looks ever accomplished for Photosystem II in Synechocystis.
“At this resolution, we can see