This technique, fast and easy to perform, allows direct visualization of proteins (from 50-100 kDa). The embedding of these proteins with heavy atoms yields highly contrasted images. Although this procedure only gives structural information from the surface of the object, it is required for checking any biological sample before a cryo-electron microscopy study or any crystallization step.
Cryo-Electron Microscopy and 3D Analysis
This technique does not require any chemical fixation or stain and thus better preserves the structure of the object. More complicated to run than the negative stain procedure, it consists in freezing thin hydrated samples very fast in liquid ethane, in order to fix them in amorphous ice. This method both allows to preserve the native structure of the specimen and to access the internal structure of macromolecular complexes. Since no stain is added, the contrast obtained on the images is very low and 3D analysis is then required. During 3D analysis low contrasted images are averaged in order to increase the signal to noise ratio. Images are 2D projections of a same object in different orientations. These projections are mathematically combined to obtain a 3D structure of the object of interest.
The EM platform provides three types of services
– Quality control (negative staining)
– Cryo-electron microscopy
Native biological sample analysis ; morphological analysis and/or 3D reconstruction.
– Cellular electron microscopy
The platform also provides access to equipments under certain conditions
Scientific collaborations, that require specific developments or strong expertise, are possible upon requests.
Daphna Fenel ; Benoit Gallet ; Christine Moriscot ; Emmanuelle Neumann ; Guy Schoehn ; Lefteris Zarkadas
See the dedicated section : Group Equipment.
If you use EM platform results, please notify in your acknowledgements :
« This work used the EM facilities at the Grenoble Instruct-ERIC Center (ISBG ; UMS 3518 CNRS CEA-UGA-EMBL) with support from the French Infrastructure for Integrated Structural Biology (FRISBI ; ANR-10-INSB-05-02) and GRAL, a project of the University Grenoble Alpes graduate school (Ecoles Universitaires de Recherche) CBH-EUR-GS (ANR-17-EURE-0003) within the Grenoble Partnership for Structural Biology. The IBS Electron Microscope facility is supported by the Auvergne Rhône-Alpes Region, the Fonds Feder, the Fondation pour la Recherche Médicale and GIS-IBiSA. »
Access and costs
PSB members, academia and industry (see prices).
IBS building, ground floor, Group Methods and Electron Microscopy.
The platform is certified ISO9001-NFX 50-900.