Scientific Achievement

  • Researchers in the Photosynthetic Systems program has provided insights into metal site structures of metalloproteins in steady/trapped states at cryogenic temperatures with a X-ray Absorption Spectroscopy (XAS) using synchrotrons. The short duration and bright X-ray pulses at XFELs make studying the dynamics of metalloproteins at room temperature possible. Our approach using a drop on tape method and a crystal analyzer to suppress the background enables shot by shot, time-resolved XAS measurements at XFELs

Significance and Impact

  • XAS spectra obtained using the background-suppression approach required 15 min compared to 12 h of data collection with the conventional approach to obtain a similar S/N. This significant advance will be important for studying the dynamics of metalloproteins, which play crucial roles in important processes relevant to health and energy

Research Details

  • Mn/Fe XAS of PS II/PS I from cyanobacteria T. vestitus were measured using a crystal analyzer to discriminate the Mn/Fe Kα fluorescence from the large background signal.
  • Data were treated on a shot-by-shot basis to take into account variations in the sample drops and the X-ray pulses at XFELs

I. Bogacz, E. Szilagyi, H. Makita, P. S. Simon, M. Zhang, M. D. Doyle, K. Chatterjee, M. Kretzschmar, P. Chernev, N. Croy, M.-H. Cheah, M. Dasgupta, I. Nangca, T. Fransson, A. Bhowmick, A. S. Brewster, N. K. Sauter, S. Owada, K. Tono, S. Zerdane, A. Oggenfuss, D. Babich, M. Sander, R. Mankowsky, H. T. Lemke, L. B. Gee, T. Sato, T. Kroll, J. Messinger, R. Alonso-Mori, U. Bergmann, D. Sokaras, V. K. Yachandra, J. Kern, J. Yano, Journal of the American Chemical Society (2025).

DOI:10.1021/acs.jpclett.5c00399

Work was performed at Lawrence Berkeley National Lab, Linac Coherent Light Source, and Stanford University.