ASTEC: an automated system for sitting-drop protein crystallization

An automated system for protein crystallization that is based on the vapor diffusion method has been developed using novel sitting-drop supports for standard Linbro plates. Laboratory robotics have been designed for liquid handling of stock solutions, silicone-grease dispensing and coverslip transfer. The system can handle up to four crystallization plates (96 wells) and ten stock solutions, without any user attendance. The software allows specification of several experimental parameters and records experiments, which may be accessed by the use of a bar-code label. Experiments may be conducted according to a user's specific design, a screening test or an incomplete factorial design. The system is capable of pipetting viscous solutions such as polyethylene glycol with good reproducibility. Automatic well-sealing techniques are discussed and preliminary protein-crystallization results are presented.