Seminar | February 3 | 2-3 p.m. | 277 Cory Hall
Dr. Junko Yano, LBNL, Molecular Biophysics and Integrated Bioimaging
Berkeley Nanosciences and Nanoengineering Institute
The metal centres in metalloenzymes and molecular catalysts are responsible for the rearrangement of atoms and electrons during complex chemical reactions, and they enable selective pathways of charge and spin transfer, bond breaking/making, and the formation of new molecules. Mapping the electronic structural changes at the metal sites during the reactions gives a unique mechanistic insight that has been difficult to obtain to date. The development of X-ray free-electron lasers (XFELs) enables powerful new probes of electronic structure dynamics to advance our understanding of metalloenzymes. Our group is studying the mechanisms of the catalytic reactions in both natural and inorganic photosynthetic systems. Using X-ray free electron lasers (XFELs) as tools, we are studying how the catalysts do multielectron reactions, by following the reaction under functional conditions.
We have developed spectroscopy and diffraction techniques necessary to fully utilize the capability of XFELs for a wide variety of metalloenzymes, and to study their chemistry under functional conditions. One such method is simultaneous data collection for X-ray crystallography and X-ray spectroscopy, to look at the overall structural changes of proteins and the chemical changes at metal catalytic sites. In parallel to the detection techniques, we have developed an efficient sample delivery method that involves deposition of droplets on a conveyor belt. This 'Droplet on Tape' (DOT) method, delivers a single drop of the crystal suspension or solution sample onto a tape, which then can be transported to the X-ray intersection point with a variable delay in time. In the process, the sample is photochemically or chemically activated at various time delays to capture reaction intermediates with crystallography and spectroscopy.
The presentation will cover our group's recent results in metalloenzyme research, in particular, for the study of the water oxidation reaction in natural photosynthesis, using X-ray crystallography and X-ray spectroscopy at LCLS (LINAC Coherent Light Source).
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Junko Yano is Interim Director of the Bio-imaging Division at LBNL. She did her PhD at Osaka Univ and postdoc at Hebrew Univ Jerusalem, and joined the Lab staff in 2003.
victorr@eecs.berkeley.edu, 510-643-6681
Avi Rosenzweig, victorr@eecs.berkeley.edu, 510-643-6681
