Abstract

X-ray crystallography requires crystals of adequate size and quality for data collection, and their production can be the bottleneck in structure analysis. The problem of growing adequate crystals involves using capillary tubes and different gel media. This has allowed the production of crystals having many less defects. Indeed, protein and virus crystals grown in such gels have enhanced diffraction properties, including sharper Bragg reflections, higher diffraction intensities with regard to the background noise or a higher diffraction limit with regard to that of crystals that are grown in the solution. Despite the discovery of these benefits, gels are largely under-exploited by protein crystal growers. The same holds for counter diffusion, a crystallisation method in which capillary forces exerted in cylindrical tubes of small diameter strongly reduce convection and stabilize the concentration gradients that exist around growing crystals. The aim of this seminar is to familiarize the audience with technically simple and efficient crystallisation methods for optimizing the quality of crystals of a variety of biological macromolecules.