Electrospray Ion Beam Deposition and Single Molecule Imaging Group


The group is developing and applying a novel, atomically precise surface preparation method, electrospray ion beam deposition (ES-IBD), which is based on the preparative use of mass spectrometry. We use this method to enable atomically resolved microscopy of individual molecules to investigate the structure and properties of complex molecular systems. This encompasses synthetic as well as biological molecules. Further, we employ the specific properties of  ES-IBD to fabricate novel, covalently bonded molecular surface coatings. 

ESIBD+cryoEM preprint

Cryo-EM of soft-landed beta-galactosidase: Gas-phase and native structures are remarkably similar


In this manuscript, we show that the structure of a gas phase protein can be determined at near- atomic (2.6 Å) resolution by cryo-EM. To make this possible we developed a workflow with bespoke hardware: native electrospray ion-beam deposition (ESIBD), consisting of native electrospray ionization, mass selection, gentle landing of the protein ions, in-situ ice embedding, and clean cryo- transfer.

we demonstrate the following key points:

  • We present a 2.6 Å cryo-EM density map of the tetrameric protein complex β-galactosidase. This resolution allows us to determine and analyze structural changes on the side-chain level.

  • We identify a single dominating gas-phase structure which retains the native secondary and tertiary structure to a high degree.

  • We observe compaction of the tetrameric complex, due to closing of cavities and grooves upon removal of water.

  • MD simulations identify dehydration as the main driver of the observed structural changes.

A Preparative Mass Spectrometer for Native Deposition

New article in ACS nano

Graphical Table of Contents which illustrates the key steps conversion and the deposition process.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.

Combining native MS and cryo-EM

New preprint

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.