Skip to comments.Photosynthesis: A New Way of Looking at Photosystem II
Posted on 06/06/2012 9:35:55 PM PDT by neverdem
Future prospects for clean, green, renewable energy may hinge upon our ability to mimic and improve upon photosynthesis -- the process by which green plants, algae and some bacteria convert solar energy into electrochemical energy. An artificial version of photosynthesis, for example, could use sunlight to produce liquid fuels from nothing more than carbon dioxide and water. First, however, scientists need a better understanding of how a large complex of proteins, called photosystem II, is able to split water molecules into oxygen, electrons and hydrogen ions (protons). A new road to reaching this understanding has now been opened by an international team of researchers, led by scientists at the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) and SLAC National Accelerator Laboratory.
Using ultrafast, intensely bright pulses of X-rays from SLAC's Linac Coherent Light Source (LCLS), the research team produced the first ever images at room temperature of microcrystals of the photosystem II complex. Previous imaging studies, using X-rays generated via synchrotron radiation sources, required cryogenic freezing, which alters the samples. Also, to catalyze its reactions, photosystem II relies upon an enzyme that contains a manganese-calcium cluster that is highly sensitive to radiation. With the high-intensity femtosecond X-ray pulses of the LCLS, the research team was able to record intact images of these clusters before the radiation destroyed them.
"We have demonstrated that the 'probe before destroy' strategy of the LCLS is successful even for the highly-sensitive oxygen bridged manganese-calcium cluster in photosystem II at room temperature," says Vittal Yachandra, a chemist with Berkeley Lab's Physical Biosciences Division. "This is an important step toward future studies for resolving the composition and atomic structure of the manganese-calcium cluster in the photosystem II complex during the critical formation of oxygen molecules."
Yachandra is one of the corresponding authors of...
(Excerpt) Read more at sciencedaily.com ...
Extending Melvin Calvin’s work (also of UC Berkeley.)
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Where does Photosynthesis sit wrt the total energy available?
Bookmark for later.
This is pretty cool.
I wonder if there’s a way to use this system to image a protein that, so far, has resisted any attempts at crystalization and is highly unstable. Well... that’s something to think about if I decide to apply for some grant money.
There are too many unknowns involved. Photosynthesis is probably the cheapest way to recapture carbon as an energy source. I'd rather see the government fund such basic science than subsidize current types of renewable energy that can't compete with natural gas.
The beams generated by the device could, for instance, help materials scientists to make better solar materials by tracking the paths of electrons through solar cells, and might allow chemists to trace the ultrafast dynamics of photosynthesis and catalysis.
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