An international team led by researchers in Berkeley Lab’s Molecular Biophysics and Integrated Bioimaging (MBIB) Division has revealed a key step in the molecular mechanism behind the water splitting reaction of photosynthesis. The finding could help inform the design of renewable energy technology.
“Life depends on the oxygen that plants and algae split from water; how they do it is still a mystery, but scientists, including our team, are slowly peeling away the layers to get to the answer,” said MBIB senior scientist Vittal Yachandra, co-lead author of a new study published in PNAS that captured the reaction in a breakthrough “molecular movie.”
The team used an instrument that they designed and fabricated to analyze photosynthetic proteins using both X-ray crystallography and X-ray emission spectroscopy. This dual approach generates chemical and protein structure information from the same sample at the same time. The imaging was performed with the X-ray free-electron laser (XFEL) at the LCLS at SLAC National Laboratory, and at SACLA in Japan.
Traditional crystallography methods often require sample proteins to be frozen; consequently, they can only generate snapshots of static proteins. This limitation makes it difficult for scientists to get a handle on how proteins actually behave in living organisms, because the molecules morph between different physical states during chemical reactions.
“The water-splitting reaction in photosynthesis is a cyclical process that needs four photons and cycles between four stable ‘states,’” said MBIB senior scientist Junko Yano, co-lead author on the study. “Previously, we could only take pictures of these four states. But by taking multiple snapshots in time, we now can visualize how one state goes to the other.”
Additional Biosciences Area co-authors include: Paul Adams, Asmit Bhowmick, Isabel Bogacz, Robert Bolotovsky, Aaron Brewster, Ruchira Chatterjee, Sheraz Gul, James Holton, Jan Kern, In-Sik Kim, Louise Lassalle, Derek Mendez, Nigel Moriarty, Trent Northen, Cindy Pham, Nicholas Saichek, Nicholas Sauter, Philipp Simon, Kyle Sutherlin, and Iris Young.
Read more in the Berkeley Lab News Center.