ASTEC: an automated system for sitting-drop protein crystallization

Abstract

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.

Crystallization of the 10-23 DNA enzyme using a combinatorial screen of paired oligonucleotides

“…It typically took 20 min to set up the plate of 24 drops for the screen described in this study. The task of distributing materials to the crystallization wells could be accomplished with a robot (Soriano & Fontecilla-Camps, 1993;Chayen et al, 1994). The use of automated pipeting would signi®cantly shorten the time required to set up the screen and thereby allow more variants to be surveyed.…”

A Spreadsheet Approach to Automated Protein Crystallization

“…Several crystallization robots with a comprehensive dedicated user interface have been described (Chayen et al, 1990(Chayen et al, , 1994Cox & Weber, 1987;Oldfield et al, 1991;Rubin et al, 1991;Sadaoui et al, 1994;Soriano & Fontecilla-Camps, 1993;Ward et al, 1988). However, so far only a semi-automated system based on a handheld motorized syringe with an interface based on a spreadsheet program has been described (Eisel6, 1993).…”

“…In some robotic systems (Kelders et al, 1987;Oldfield et al, 1991;Soriano & Fontecilla-Camps, 1993) the reservoir is mixed automatically by repeated aspirating/dispensing of the well content. That procedure is relatively slow and may not work for very viscous solutions.…”

“…The preparation of a set of protein crystallization experiments typically involves the dispensing of a number of different solutions in varying amounts to form the well solutions and subsequent preparation of the drops by mixing these with protein solution. Automatic preparation of vapour-diffusion experiments (Cox & Weber, 1987;Kelders, Kalk, Gros & Hol, 1987;Oldfield, Ceska & Brady, 1991;Rubin, Talafous & Larsen, 1991;Sadaoui, Janin & Lewit-Bentley, 1994;Soriano & Fontecilla-Camps, 1993;Ward, Perozzo & Zuk, 1988) and microbatch trials in wells filled with oil (Chayen, Shaw Stewart, Maeder & Blow, 1990;Chayen, Shaw Stewart & Baldock, 1994) have been described. These automated procedures have proven highly beneficial in terms of speed and reproducibility.…”

XAct: a program for construction, automated setup and bookkeeping of crystallization experiments

“…Some approaches use commercially available robotics equipment, customized via its setup software and locally developed software (Ward et al, 1988;Rubin et al, 1991;Cox & Weber, 1987), while other systems started as experimental prototypes and later developed into commercial products [for example, that of Chayen et al (1990Chayen et al ( , 1994, now available through Douglas Instruments, Berkshire, UK (http:// www.douglas.co.uk)]. The employed instrumentation ranges from small motorized and computer-controlled pipettes (Eisele Â, 1993) to large automated laboratories that take care of tasks as diverse as liquid handling, dispensing of protein solution onto cover slips, and application of vacuum grease to seal experiments (Soriano & Fontecilla-Camps, 1993;Sadaoui et al, 1994).…”