From providing living cells with energy, to nitrogen fixation, to the splitting of water molecules, the catalytic activities of metalloenzymes proteins that contain a metal ion are vital to life on Earth. A better understanding of the chemistry behind these catalytic activities could pave the way for exciting new technologies, most prominently artificial photosynthesis systems that would provide clean, green and renewable energy. Now, researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) and the SLAC National Accelerator Laboratory have taken a major step towards achieving this goal.
Using ultrafast, intensely bright pulses of X-rays from SLAC's Linac Coherent Light Source (LCLS), the world's most powerful X-ray laser, the researchers were able to simultaneously image at room temperature the atomic and electronic structures of photosystem II, a metalloenzyme critical to photosynthesis.
"This is the first time that femtosecond X-ray pulses have been used for the simultaneous collection of both X-ray diffraction (XRD) and X-ray emission spectroscopy (XES) at room temperature of a metalloenzyme crystal," says Junko Yano, a chemist with Berkeley Lab's Physical Biosciences Division who was one of the leaders of this research. "Collecting both diffraction and spectroscopy data from the same crystal under the same conditions is required for a detailed understanding of the mechanisms behind metalloenzyme catalysis."
Yano is a corresponding author, along with Vittal Yachandra, also a chemist with Berkeley Lab's Physical Biosciences Division, and Uwe Bergmann, a physicist with SLAC, of a paper about this research in the journal Science. The paper is titled "Simultaneous Femtosecond X-ray Spectroscopy and Diffraction of Photosystem II at Room Temperature." (See below for full list of co-authors.)
Photosystem II, a large protein complex in green plants, algae and cyanobac
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DOE/Lawrence Berkeley National Laboratory