Automated Crystal Harvesting, Freezing and X-Ray Diffraction

This system is an evolution of the G-Rob systems. G-Rob system was developed on protein crystallography beamline FIP-BM30A at the ESRF. G-Rob, A 6-axis robotic arm based system, is a fully integrated device for crystallography beamlines and laboratories. G-Rob is an “all in one” system. Thanks to its tool changer, it goes automatically from one application to another. A new tool for the robot and an adapted environment has been developed to allow G-Rob in situ crystal manipulation from crystallization plates. The harvesting step allows mounting the crystal on the robot’s fishing tool with X-ray transparent terminal organs. Once the crystal has been fished, an automated cycle prepares the crystal for diffraction trough cryoprotection and flash cooling steps. Thus the sample is ready for X-ray diffraction without dismounting and human manipulation. At this point, the classical G-Rob’s goniometer function [1] is used for data collection. A visualization bench with an inverted 90° angled microscope and an image processing programs has been developed to offer the ability to evaluate crystals positions in Greiner CrystalQuickTM X plates. The video acquired from the microscope is processed to find three corners of the square well containing the crystallization drop. Accordingly, a click on the centre of an interested crystal will save the coordinates of the crystal in the well frame. The same coordinates are used in situ X-ray analysis of the crystal, in its crystallization drop using G-Rob [2], prior to harvesting. With this new function, G-Rob can go from in situ analysis to data collection on frozen crystal with no need of manual manipulation. All the process can then be operated remotely.