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DTSTAMP:20230731T103959
DTSTART;TZID=America/Detroit:20230803T130000
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SUMMARY:Workshop / Seminar:Physics Graduate Student Symposium (PGSS) | Ultrafast Time-Resolved Spectroscopy Using Optical and X-ray Probes Elucidates the Structural and Electronic Evolution of Photoexcited Coenzyme B12
DESCRIPTION:Coenzyme B12\, also known as adenosylcobalamin (AdoCbl)\, is an important enzymatic cofactor in prokaryotic and eukaryotic species. This molecule consists of a central cobalt coordinated equatorially to a corrin ring ligand\, with a lower axial dimethylbenzimidazole α-ligand and an upper axial deoxyadenosyl β-ligand. AdoCbl’s ground state reactivity has been studied in detail\, but it was only recently that its role as chromophore in the bacterial photoreceptor protein CarH showed a biological usage of the molecule’s inherent light-sensitivity. The light-induced response of AdoCbl can be characterized using time-resolved spectroscopies. Presently\, our group has performed studies with transient absorption (TA) UV-Vis spectroscopy\, X-ray absorption spectroscopy\, and X-ray emission spectroscopy. TA spectroscopy provides electronic information about the valence orbitals of the system. The X-ray spectroscopies are element-specific probes of the electronic and atomic structure around the central cobalt atom of the AdoCbl. These studies reveal a distinct solvent-dependence of AdoCbl photochemistry as well as a dynamic dance of structural distortions immediately following light excitation. Time-dependent density functional theory (TD-DFT) and finite difference method (FDM) calculations are used to simulate the X-ray absorption and emission spectra. This information is crucial for understanding the CarH protein more deeply as well as bringing cobalamin-based light-mediated drug delivery and optogenetic applications closer to reality.
UID:108481-21819637@events.umich.edu
URL:https://events.umich.edu/event/108481
CLASS:PUBLIC
STATUS:CONFIRMED
CATEGORIES:Graduate Students,Physics
LOCATION:West Hall - 340
CONTACT:
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