We have modified a commercial mass spectrometer for the native deposition of large, native protein complexes. To this end, we added a landing module, and modified the vacuum system to increase transmission. The new instrument has a narrow beam energy distribution for gentle deposition. It can produce mass-selected samples for AFM and TEM from native protein ion beams. With the instrument, we demonstrate the non-covalent protein complex ADH retains enzymatic activity after deposition and rehydration.

For the full article, click here.

Our recent preprint, Mass-selective and ice-free cryo-EM protein sample preparation via native electrospray ion-beam deposition, has now been published in PNAS Nexus. Click here for the full article.

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In our latest preprint, Mass-selective and ice-free cryo-EM protein sample preparation via native electrospray ion-beam deposition, we introduce native electrospray ion-beam deposition (native ES-IBD), a mass-selective sample preparation workflow for cryo-EM. Folded protein ions are generated by native electrospray ionization, mass-filtered, and gently deposited on cryo-EM grids, which are subsequently frozen in liquid nitrogen. Native ES-IBD has the potential to complement and accelerate established cryo-EM sample preparation workflows, by direct correlation between cryo-EM maps with precise information on composition and conformation. We show 3D reconstructions of protein assemblies purified in the gas-phase.

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Our recent paper in Physical Review Letters, Fast Molecular Compression by a Hyperthermal Collision Gives Bond-Selective Mechanochemistry, has garnered interest in many review publications. 

It has been featured in Nature Reviews Chemistry , New Scientist, and Chemistry World, published by the Royal Society of Chemistry, as well as being featured in Viewpoint in Physical Review Letters. 

About the experiment: Using electrospray ion beam deposition, we collide the complex molecule Reichardt’s dye at low, hyperthermal translational energy with a copper surface and image the outcome at single-molecule level by STM. We observe bond-selective reaction induced by the translational kinetic energy. The collision impulse compresses the molecule and bends specific bonds, prompting them to react selectively. This dynamics drives the system to seek thermally inaccessible reactive pathways, since the compression timescale (subpicosecond) is much shorter than the thermalization timescale (nanosecond). The fate of the molecule depends on its orientation when hitting the surface - it can either remain intact, crack or split. This gives great insights into better understanding mechanochemistry.

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In our recent paper in Nature we were able to show direct imaging of single glycan molecules that are isolated by mass-selective, soft-landing electro spray ion beam deposition and imaged by low-temperature tunnelling microscopy. The sub-nanometre resolution of the technique enables the visualisation of glycan connectivity and discrimination between regioisomers. Direct glycan imaging is an important  step toward a better understanding of the structure of carbohydrates. 

The publication was featured in Nature Methods.