SKM 2023 – scientific programme

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O: Fachverband Oberflächenphysik

O 26: Poster: New Methods

O 26.5: Poster

Monday, March 27, 2023, 18:00–20:00, P2/EG

High-Resolution Imaging of Protein Complexes Enabled by Electrospray Ion-Beam Deposition Sample Preparation — •Asha Thompson, Tim Esser, Markó Grabarics, Isabelle Legge, and Stephan Rauschenbach — University of Oxford, Department of Chemistry, United Kingdom

Structural characterisation of biological molecules such as proteins is essential for insight into their processes and interactions within cells. Samples of mass-filtered molecules adsorbed onto surfaces can be obtained using preparative mass spectrometry techniques such as electrospray ion-beam deposition (ES-IBD). ES-IBD generates intense beams of native proteins which are soft-landed onto surfaces. This produces uncontaminated samples which can be further characterised by transmission electron microscopy (EM) or scanning probe microscopy (SPM).

Here we present the application of this approach for the imaging of proteins showing examples of soluble and of membrane proteins, such as Human C Reactive protein, ferritin, Beta-galactosidase and Aquaporin-Z. We can show that the shape of the protein, its subunit conformation, and stoichiometry are retained, which points to intact secondary structure. [1] We intend to extend this approach to map the interactions of antibodies and their targets in order to provide information about the binding sight, useful for pharmacology.

[1] T. K. Esser, et al, Mass selective and ion-free electron cryomicroscopy protein sample preparation, PNAS nexus, Volume 1, issue 4, 2022