Crop Biotech Update

Scientists Watch Photosynthesis in Action

July 23, 2014

An international team of scientists has caught an important step of photosynthesis for the first time. Led by Prof. Petra Fromme from Arizona State University, the team used the world's most powerful X-ray flashlight at the SLAC National Accelerator Laboratory in the U.S. to record still frames of a molecular complex called photosystem II as it splits water into hydrogen and oxygen, a process that maintains the oxygen in the earth's atmosphere.

Professor Fromme said "This is the very first scene of a molecular movie showing light-driven water splitting in photosystem II, the mechanism which makes all oxygen in the atmosphere." The observations show with molecular resolution that photosystem II significantly changes shape during this process.  To observe photosystem II in action, the team grew tiny nano-crystals of the photosystem II complex of Thermosynechococcus elongatus cyanobacteria . These crystals were illuminated with a visible laser to start the water splitting process, which is otherwise driven by sunlight. The researchers used double light flashes to trigger the transition from stage S1 to stage S3, as this transition was expected to show the largest dynamics.

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