Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 43: Poster Session II - MA 141/144 (Surface Spectroscopy on Kondo Systems; Frontiers of Surface Sensitive Electron Microscopy; Methods: Scanning Probe Techniques+Electronic Structure Theory+Other; Time-Resolved Spectroscopy of Surface Dynamics with EUV and XUV Radiation; joined by SYNF posters)
O 43.6: Poster
Dienstag, 26. Februar 2008, 18:30–19:30, Poster F
Transmission photoemission electron microscopy for lateral mapping of the X-ray absorption structure of a metalloprotein in a liquid cell — •Daniel Panzer1, Christian Beck2, Jochen Maul1, Marco Möller2, Heinz Decker2, and Gerd Schönhense1 — 1Institut fuer Physik, Staudinger Weg 7, Johannes Gutenberg-Universitaet, D-55099 Mainz — 2Institut fuer Molekulare Biophysik, Welderweg 26, D-55099 Mainz
The mechanism of oxygen incorporation in respiratoty proteins is subject of intensive discussion. We use photoemission electron microscopy in an X-ray transmission mode for full-field imaging of the X-ray absorption structure of copper in the respiratory metalloprotein hemocyanin KLH1. It contains 160 oxygen bonding sites. Each site reversibly binds one molecule oxygen between two copper atoms. In our setup, hemocyanin is dissolved in aqueous solution and enclosed in an ultra-high vacuum compatible liquid sample cell with silicon nitride membranes. The local X-ray absorption structure of the liquid sample is converted into photoelectrons at the microscope side of the cell acting as a photocathode. In this way, different copper valences are laterally distinguished under in vivo-like conditions, attributed to Cu(I) in the deoxy-state and Cu(II) in the oxy-state.
This project was funded by the DPG (SCHO 341/7).