Structural Biology Programme

Electron Microscopy Unit

Head of Unit:  Jasminka Boskovic
Research highlights

The Electron Microscopy Unit is a research facility that assists with different biological scientific projects ranging from the macromolecular to the cellular level. The EM Unit’s scope of work includes sample preparation protocols, negative staining, cryo-EM, and data collection methods, as well as 2D and 3D data processing.

In collaboration with CNIO’s Structural Bases of Genome Integrity Group (Structural Biology Programme), we carried out negative staining electron microscopy to gain insight into the molecular architecture of DHO-ATC hexamers. The EM analysis clearly indicated that despite crosslinking, the particle presents a structural flexibility that prevents the determination of a complete 3D model. A combination of structural and biophysical studies enabled us to propose a model that sets the DHO and ATC complex as the central element in the architecture of multifunctional protein CAD. Our model suggests that CAD is more than the sum of its parts, and that the detailed study of the pieces will give limited information in comparison with the complexity that would be revealed by the structural determination of the full-length particle.

We continued our collaboration with Dr. Iván Ventoso, from the Centro de Biología Molecular ‘Severo Ochoa’ (CSIC-UAM) and the Departamento de Biología Molecular, Universidad Autónoma de Madrid (UAM). The EM Unit participated in the study of the topology and dynamics of the scanning ribosomal 43S preinitiation complex (PIC). Our data supports a model where the eIF4F complex works at the leading edge of the scanning PIC, rather than acting as a simple clamp to prevent backsliding as previously suggested.

We have advanced in our understanding of PI(4,5)P2-mediated induction of Focal Adhesion Kinase (FAK) clustering at the cell membrane by applying 2D electron crystallography. This work is the continuation of our collaboration with CNIO’s Cell Signalling and Adhesion Group (Structural Biology Programme).