Automated screening of 2D crystallization trials using transmission electron microscopy: A high-throughput tool-chain for sample preparation and microscopic analysis

Nicolas Coudray (1) , Gilles Hermann (1) , Daniel Caujolle-Bert (2) , Argyro Karathanou (1) , Françoise Erne-Brand (2) , Jean-Luc Buessler (1) , Paméla Daum (1) , Jürgen M Plitzko (3) , Mohamed Chami (2) , Urs Mueller (2) , Hubert Kihl (1) , Jean-Philippe Urban (1) , Andreas Engel (2, 4) , Hervé W. Rémigy (5, 6)

1 MIPS - Modélisation, Intelligence, Processus et Système
2 C-CINA - M.E. Mueller Institute for Structural Biology
3 Department of Molecular Structural Biology [Martinsried]
4 Department of Pharmacology
5 C-CINA - M.E. Mueller Institute for Structural Biology
6 FEI Electron Optics

We have built and extensively tested a tool-chain to prepare and screen two-dimensional crystals of membrane proteins by transmission electron microscopy (TEM) at room temperature. This automated process is an extension of a new procedure described recently that allows membrane protein 2D crystallization in parallel (Iacovache et al., 2010). The system includes a gantry robot that transfers and prepares the crystalline solutions on grids suitable for TEM analysis and an entirely automated microscope that can analyze 96 grids at once without human interference. The operation of the system at the user level is solely controlled within the MATLAB environment: the commands to perform sample handling (loading/ unloading in the microscope), microscope steering (magnification, focus, image acquisition, etc.) as well as automatic crystal detection have been implemented. Different types of thin samples can efficiently be screened provided that the particular detection algorithm is adapted to the specific task. Hence, operating time can be shared between multiple users. This is a major step towards the integration of transmission electron microscopy into a high throughput work-flow.

Mots clés: Automation; 2D crystallization; Electron crystallography; Grid preparation; High throughput; Image processing; Membrane protein; Negative staining

Domaines: Traitement du signal et de l'image [eess.SP]; Traitement du signal et de l'image [eess.SP]

Nicolas Coudray, Gilles Hermann, Daniel Caujolle-Bert, Argyro Karathanou, Françoise Erne-Brand, et al.. Automated screening of 2D crystallization trials using transmission electron microscopy: A high-throughput tool-chain for sample preparation and microscopic analysis. Journal of Structural Biology, 2010, 173, pp.365-374. ⟨10.1016/j.jsb.2010.09.019⟩. ⟨hal-00851864⟩