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Counter-Diffusion Protein Crystallization Kit [Crystal Tube Kit]


Counter-diffusion is a crystallization method in a capillary in which a protein and a reservoir solution diffuse into each other from opposite directions.1), 2)  Both the protein and the precipitant solutions are set to diffuse through the gel, and the concentration gradients of both solutions form in the capillary. The capillary can continuously scan a wide range of crystallization conditions unless crystallization occurs. By fixing the precipitant concentration higher, you can scan a wider range of crystallization conditions. Therefore, a single capillary may be equivalent to many drops in the vapor-diffusion method.

1) McPherson A., Crystallization of Biological Macromolecules, Cold Spring Harbor Lab. Press (1999)
2) Garcia-Ruiz, J.M., Moreno, A.: Acta Cryst., D50, 484-490(1994)

Feature and Advantages

Size: Very little space is required for crystallization set-up.

Easy Set-up: The Gel-tube already contains agarose in the silicon tube, making the crystallization set up very easy.

Small Protein Sample: Only 2 micro-L per screening. Only 10 micro-L per diffractive-grade crystal.

Favorable Crystallization Conditions: The timing of crystallization can be controlled by Gel-tube length, the amount of protein solution in a capillary, and the concentration of protein and precipitant solution.

High Reproducibility and Reliability: JAXA uses this method for crystallization in space. After crystallizing over 400 different proteins, the Crystal Tube kit has proven its reliability and high reproducibility.

Long-term Stability of Crystals: Crystals grown in the capillary are stable over the long term, making it easy to soak crystals with another compound, such as a ligand or cryoprotectant.

Membrane Protein Crystallization: Phase separation due to concentrated detergent in the solution does not occur.

User Manual: Download our user manual at to learn about crystallization using counter-diffusion method.


< Protein Crystals Grown in the Crystal Tube >


< Example >
Buffer + 30% PEG 4000 + 0–700 mM NaCl

Conditions in which crystals, oil and/or precipitate were observed are indicated by “C”, “O” or “P”, respectively.

  • There is an optimum salt concentration for PEG as the precipitant, as shown in the table. If too low, crystals will not grow. If too high, precipitate or oil will be obtained.
  • Crystallization can sometimes be accelerated if the protein and the reservoir solutions are pre-mixed 1:1 before crystallization set-up.
    Reference: ICCBM12 (2008) Program & Abstracts Book 128

Product List

Product Name Cat# Quantity Price

Crystal-Tube GT-R

CFS-MB2004-CRT200 1SET

¥ 90,000
$ 1200
€ 900

Screw-top test tube

CFS-MB2004-CRT201 24UNIT

¥ 55,000
$ 734
€ 550



¥ 24,000
$ 320
€ 240

Capillary, 0.3mm i.d

CFS-MB2004-CRT203 30UNIT

¥ 24,000
$ 320
€ 240

Capillary, 0.5mm i.d

CFS-MB2004-CRT204 20UNIT

¥ 19,000
$ 254
€ 190

Starters kit

CFS-MB2004-CRT209 1SET

¥ 15,000
$ 200
€ 150

To be used for research only. DO NOT use for human gene therapy or clinical diagnosis.