For the next phase of this research, the researchers plan to study the final two steps in the photosystem II water-splitting process. Understanding how photosystem II is able to split water molecules into oxygen, electrons and hydrogen ions is crucial to the development of an effective and efficient artificial version of photosynthesis that could produce liquid fuels from nothing more than sunlight, carbon dioxide and water.
"Getting critical snapshots of the final photon steps in the photosystem II machinery would really answer all of the questions we have at the moment about how this system works," says Jan Kern, a chemist with Berkeley Lab's Physical Biosciences Division and SLAC who is the first author of the Science paper.
Says Yano, "We're interested in understanding the design principles in natural photosynthesis, which can only be obtained by collecting data from all the states and that will be useful for making artificial light-driven catalysts for water-splitting."
Beyond photosystem II and photosynthesis, the Berkeley Lab/SLAC team has demonstrated that simultaneous XRD and XES studies using ultra-short ultra-bright X-ray pulses can be used for future time-resolved studies of light-driven structural changes within protein and metal cofactors, and of chemical dynamics at the catalytic metal centers of metalloenzymes under functional conditions.
"We expect that this method will be applicable to many metalloenzymes, including those that are known to be very sensitive to X-ray photo-reduction and radiation damage, and over a wide range of time scales, starting with femtoseconds," Yano says.
|Contact: Lynn Yarris|
DOE/Lawrence Berkeley National Laboratory