Cryogenic Soft Landing Improves Structural Preservation of Protein Complexes

• Published in: Analytical chemistry (Washington) Vol. 95; no. 40; pp. 15094 - 15101
• Main Authors: Westphall, Michael S., Lee, Kenneth W., Hemme, Colin, Salome, Austin Z., Mertz, Keaton, Grant, Timothy, Coon, Joshua J.
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 10-10-2023
• Subjects: Cryoelectron Microscopy - methods; Electron microscopy; Ion beams; Mass Spectrometry; Mass spectroscopy; Preservation; Proteins; Room temperature; Soft landing; Thin films; Transmission electron microscopy
• ISSN: 0003-2700; 1520-6882; 1520-6882
• DOI: 10.1021/acs.analchem.3c03228

We describe an apparatus for the cryogenic landing of particles from the ion beam of a mass spectrometer onto transmission electron microscope grids for cryo-electron microscopy. This system also allows for the controlled formation of thin films of amorphous ice on the grid surface. We demonstrate that as compared to room temperature landings, the use of this cryogenic landing device greatly improves the structural preservation of deposited protein–protein complexes. Furthermore, landing under cryogenic conditions can increase the diversity of particle orientations, allowing for improved 3D structural interpretation. We conclude that this approach allows for the direct coupling of mass spectrometry with cryo-electron microscopy.