Projects

Cellular defense mechanisms against radiation-induced oxidative stress

PI: Célia Romão

Funded by FCT (2019-2022)

This project aims at tackling the question of cell responses to oxidative stress, both chemically- and radiation-induced. In order to understand what constitutes an excellent mechanism of response to oxidative stress, we use the model bacteria Deinococcus radiodurans, which is the most radiation-resistant organism known.

We focus on metal homeostasis, post-translational modifications and Dps proteins. Dps1 and 2 are ferritin-like proteins that in their dodecameric form are able to store Iron and Manganese, but change their oligomeric state in response to oxidative stress-inducing insults, becoming bound to DNA.

We use Macromolecular Crystallography and Cryo-electron Microscopy to study protein and protein-DNA complexes involved in cellular resistance to stress. We use Electron Tomography to visualize cellular structures pre- and post-oxidative stress insult, and X-ray fluorescence nano imaging to identify metal distribution in the cell. The structural studies are complemented with an array of biochemical techniques.

Horizon2020 Twinning project: IMpaCT - Boosting cryoEM in Portugal

PIs: Célia Romão and Pedro Matias

European funding (2019-2023)

This project aims at building knowledge of cryo-electron Microscopy at the different groups of the Macromolecular Crystallography Unit. To achieve that goal, a wide network has been established with expert groups across Europe and Israel, in the fields of Single Particle Analysis (Helsinki University), Cryo-electron Tomography and Energy-Dispersive X-ray Spectroscopy (Weizmann Institute) and data processing and refinement (Centro Nacional de Biotecnología).

In collaborations with the partners, we have collected several EM datasets of target proteins from various MXU groups. With the partners support, we are also establishing the insfrastructures and know-how at the MXU to prepare protein and cell samples for cryoEM analysis.

We have in 2020 acquired a glow discharger (used to prepare EM grids for sample deposition) and built a manual freeze-plunger (used to vitrify protein and cell samples upon deposition on the EM grid). We have also established protocols for sample preparation at the Unit, and created two lab spaces dedicated to this technique (one for negative staining, and one for sample cryo-cooling, both following safety procedures).

Glow discharger                                                                                  Freeze-plunger

Previous projects

Human RuvB-Like 2 protein and R2TP-like complexes

Supercomplexes of the respiratory chain of E. coli and B. subtillis

Na+/H+ antiporters from N. meningitidis and R. marinus