Liquid-phase Electron Microscopy in Structural and Molecular Biology

Session

Poster Session 4

Authors

Mr Gabriel Ing (2), Mr Cesare De Pace (2), Dr Silvia Acosta Gutierrez (2), Mr Gabrielle Marchello (2), Dr Simona Pilotto (2), Dr Diana Moriera Leite (2), Professor Finn Werner (2), Mr Neil Wilkinson (1), Professor Francesco Gervasio (2, 4), Dr Lorena Ruiz-Perez (2), Professor Giuseppe Battaglia (2, 3, 5)

Affiliations

1. Gatan
2. University College London
3. The Barcelona Institute of Science and Technology
4. University of Geneva
5. Catalan Institution for Research and Advanced Studies (ICREA)

Keywords

Liquid-phase Electron Microscopy 

LPTEM 

Structural biology

RNA Polymerase

TEM 

in-situ Imaging

Low-dose imaging

Abstract text

The use of electron microscopes to study large protein complexes has transformed structural and molecular biology in the form of single particle cryo-EM. However, this method involves vitrification of samples and thus is far from the native solution state, and causes a loss of dynamic information. Liquid-phase electron microscopy (LPEM) is a developing field which uses electron transparent materials, namely silicon nitride and graphene, to create liquid cells allowing imaging of liquid samples by transmission electron microscopy. While this technique has, to date, mainly been used for inorganic materials and nanoparticles, it has enormous potential for examination of biological samples. By imaging specimens in liquids we can capture dynamic information of biological processes, including the formation of amyloid for instance. Furthermore, as the particles are freely diffusing in liquids, we can analyse the conformational states of individual particles during the experiment. Herein we present the investigation of three protein samples, with individual views of archaeal RNA polymerase and ferritin, which demonstrates the potential of  LPEM  on a single particle level. We also present amyloid-beta aggregation into toxic oligomers and larger aggregated structures. These early results show a promising future for LPEM as a method to solve dynamic molecular biological questions in solution state.