Opening a new window on the way plants generate the oxygen we breathe, researchers used an X-ray laser at the Department of Energy's (DOE) SLAC National Accelerator Laboratory to simultaneously look at the structure and chemical behavior of a natural catalyst involved in photosynthesis for the first time.
The work, made possible by the ultrafast, ultrabright X-ray pulses at SLAC's Linac Coherent Light Source (LCLS), is a breakthrough in studying atomic-scale transformations in photosynthesis and other biological and industrial processes that depend on catalysts, which efficiently speed up reactions. The research is detailed in a Feb. 14 paper in Science.
"All life that depends on oxygen is dependent on photosynthesis," said Junko Yano, a Lawrence Berkeley National Laboratory chemist and co-leader in the experiment. "If you can learn to do this as nature does it, you can apply the design principles to artificial systems, such as the creation of renewable energy sources. This is opening up the way to really learn a lot about changes going on in the catalytic cycle."
Catalysts are vital to many industrial processes, such as the production of fuels, food, pharmaceuticals and fertilizers, and represent a $12 billion-per-year market in the United States alone. Natural catalysts are also key to the chemistry of life; a major goal of X-ray science is to learn how they function in photosynthesis, which produces energy and oxygen from sunlight and water.
The LCLS experiment focused on Photosystem II, a protein complex in plants, algae and some microbes that carries out the oxygen-producing stage of photosynthesis. This four-step process takes place in a simple catalyst a cluster of calcium and manganese atoms. In each step, Photosystem II absorbs a photon of sunlight and releases a proton and an electron, which provide the energy to link two water molecules, break them apart and release an oxygen molecule.
|Contact: Andy Freeberg|
DOE/SLAC National Accelerator Laboratory