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BP: Fachverband Biologische Physik
BP 30: Protein Structure and Dynamics
BP 30.9: Vortrag
Donnerstag, 20. März 2025, 17:30–17:45, H46
Laser flash melting restores native protein conformation after cryoEM preparation by soft-landing, native electrospray ion beam deposition. — Sarah V. Barrass1, Tim K. Esser2, Nathan J. Mowry1, Lukas Eriksson2, Jakub Hruby1, Laurence Seeley3, Marcel Drabbels1, Lindsay Baker3, •Stephan Rauschenbach2, and Ulrich J. Lorenz1 — 1EPFL Lausanne — 2Univ. of Oxford, Dept. of Chem.. — 3Univ. of Oxford, Dept. of Biochem.
Electron cryo microscopy (cryoEM ) is today the dominating method for protein structure determination. Samples for cryoEM consist of thin, freestanding layers of amorphous ice in which proteins are embedded. Conventionally, these samples are prepared by shock-freezing of thin water films held in grid holes.
Alternative sample preparation methods are being developed, as the plunge-freezing method is not compatible with all types of protein sample. One of these methods is electrospray ion beam deposition (ESIBD) where mass-selected proteins from the gas-phase are landed on a thin amorphous carbon film in vacuum and embedded in ice grown from the gas phase for imaging. Recently it was shown that this method yields atomically resolved protein structures characterised by small changes in ternary structure due to dehydration.
Here we show that the dehydration can be reversed by irradiating the sample with short laser pulses, effectively melting the ice for a short time, allowing the protein to recover the native conformation, before the ice rapidly re-vitrifies.
Keywords: cryoEM; electrospray; gas-phase structure; hydration; laser flash melting