The Topaz system provides the most efficient solution for protein crystallography. Crystallization success is improved through the advantages of in situ diffraction, ultra-low sample volumes, and free interface diffusion.
The 1.96 Diffraction Capable (DC) Chip’s advanced design makes it possible to obtain high quality in situ X-ray diffraction data during the crystal screening process. This unique capability enables critical decisions to be based on diffraction data, rather than subjective assessments, such as crystal size, shape, or color.
The 4.96 TOPAZ Screening Chip requires only one microliter of protein solution per 96-reagents and handles up to four samples at once. With the 4.96 TOPAZ Screening Chip, researchers may compare the potential of many different samples to crystallize. Learn how Rx3 Pharmaceuticals takes advantage of this parallel processing approach.
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Free interface diffusion (FID) has kinetic properties that make it inherently more efficient than vapor diffusion for exploring chemical conditions that result in crystals (Salemme, 1972; Ng et al., 2003)*.
Despite its efficiency, FID was not widely adopted because it required the use of glass capillaries and significant manual effort. The introduction of TOPAZ screening chips provided an ideal solution for efficient FID implementation.
Crystallization gradient caused by FID in TOPAZ® screening chips.
Protein sample and reagent solutions are automatically loaded into diffusion chambers within the chip. When interface valves open, the two solutions mix by diffusion only. The result is a gradual increase of reagent concentration that causes crystal nucleation and growth. This slow diffusive mixing samples a wide swath of chemical space and often produces a crystallization gradient as shown above. In addition, because the chip material is gas-permeable, the mixture also undergoes a controlled process of evaporative concentration.
* Ng, J.D., Gavira, J.S., Garcia-Ruiz, J.M. (2003) Journal of Structural Biology 142: 219231.
* Salemme, R.R., (1972) Arch. Biochem. Biophys. 151: 533-539.
