Protein crystallography is an ideal approach to characterize the 3D structure of proteins linked to drug candidates and to determine the molecular basis of complexes between proteins and their partner DNA, RNA, other proteins, peptides, lipids and co-factors.
The I2BC crystallization facility (https://www.i2bc.paris-saclay.fr/structural-biology/crystallization/, labelled IBiSA) enables automated screening, analysis and optimization of macromolecule crystallization conditions. The platform is equipped with nano-volume pipetting and visualization robots, which allow set-up experiments with vapor diffusion and lipid cubic phase methods.
Know-how and technology are open to the entire scientific community (from novice to experienced crystallographers) wishing to be able to "look" at the object they are studying. The facility offers self-service access to crystallization and visualization robots and provides users with ready-to used crystallization kits and can deliver projects crystallization and crystallography in collaboration.
Sample quality and purity are crucial for crystallization. Before crystallization screening, samples must be analyzed by SDS-PAGE. Platform staff can advise users on the best purification method for their protein of interest.
The proximity of the synchrotron Soleil is also a great asset for protein crystallography. The synchrotron is a prerequisite for the characterization of new crystal unit (salt crystals versus macromolecules and optimization of buffer conditions for freezing crystals) and essential for diffraction data collection for the resolution of structures using heavy derivatives or molecular replacement.
Tecan Genesis, Freedom Evo (TECAN) and STRAlet (Hamilton): These liquid-handling robots are used to fill crystallisation reservoirs with screening kit solutions and the custom design of optimization grids (70-150 µL). They can also performed large volume crystallization drops (1 µL to 2µL).
Cartesian Microsys (PROTEIGEN), Mosquito® and Mosquito® LCP (TTP LabTech): The robots are used to dispense nanolitre volumes (50 nL to 1 µL) for the screening and the optimization of crystallization conditions.
RockImager® 182 and two RockImager® 1000 (Formulatrix): These cabinets store and automatically take images of plates at regular intervals at 6°C and 20°C. Images are accessible to users via a web-interface. One of the RockImager 1000 is equipped with UV Imaging Option allowing the detection of tryptophan fluorescence thus distinguishing protein crystals from salt crystals.