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BP: Fachverband Biologische Physik
BP 9: Bioimaging
BP 9.2: Talk
Tuesday, September 6, 2022, 09:45–10:00, H16
Phase reconstruction of low-energy electron holograms of individual proteins — •Hannah Ochner1, Sven Szilagyi1, Moritz Edte1, Stephan Rauschenbach1,2, Luigi Malavolti1, and Klaus Kern1,3 — 1Max Planck Institute for Solid State Research, Stuttgart — 2Department of Chemistry, University of Oxford — 3Institut de Physique, École Polytechnique Fédérale de Lausanne
Low-energy electron holography (LEEH) can image proteins and their conformational variability on the single-molecule level [1,2]. However, the technique does not yield a real-space image, but rather a hologram from which the information about the molecule needs to be recovered via a reconstruction process. While a one-step reconstruction process can reproduce molecular size and shape via amplitude imaging, it cannot directly recover the phase information encoded in the hologram. Here, we apply an iterative phase retrieval algorithm to experimentally acquired low-energy electron holograms of proteins. This allows us to reconstruct the phase shift induced by the protein along with its amplitude distribution. We provide evidence that phase imaging is sensitive to changes in local potential, as indicated by the strong correlation between reconstructed phase shift and the number of scatterers in the electron path, and the strong phase signatures induced by localised charges. LEEH phase imaging thus yields insights into structural features beyond size and shape and could, at high spatial resolution, open up the possibility of chemically sensitive single-molecule imaging.
[1] PNAS,2017;114(7) [2] PNAS,2021;118(51) e2112651118