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Crystallization device for obtaining crystals for X-ray diffraction experiment using counter-diffusion method.

Crystal Tube - SGT (Sealbag Gel Tube)


Series of devices are designed for obtaining protein crystals with Counter diffusion method. The series features starter kit and helping assembly effective for protein crystallization.

*What is Counter-diffusion method?

Protein and reservoir solutions diffuse each other from opposite direction through the gel-tube and form concentration gradient along the capillary. It is called “counter-diffusion” method (1)(2). If the precipitant concentration is set higher, wider range of crystallization condition can be scanned. A crystal starts to grow where the concentration of protein and the precipitant is optimized for crystallization. This type of experiment can explore a wide range of crystallization conditions in one single experiment, so that there is high possibility and reproducibility of obtaining high-quality crystals in a single experiment (3)(Fig1).

Kit Component

Crystal Tube SGT kit
  • Sealing Gel Tube (JCB-SGT)
  • Gel Tube (10cm)
  • Capillary (Φ0.5mm×47mm)
SGT Loading Tools
  • Down Controller (with or without)
  • Heat Controller
  • Point Sealer
  • SGT Holder
  • Silicon Tubing (50cm)
  • Sealing Compound


*Low price and high density

JCB-SGT is a high-density crystallization cell used for Japan Aerospace Exploration Agency’ s Protein Crystal Growth Experiment (JAXA PCG).Neither robot nor special device is required for set-up.

*Easy preparation

Gel tubing (gel in silicone tubing) can make the experimental set-up easy.

*Less volume of protein

2µl / capillary for optimization of crystallization condition and 8µl / capillary for growing crystals for X-ray diffraction experiment.

*Mild crystallization

Crystallization condition can be controlled by the length of gel-tube and concentration of protein and precipitant solutions. The condition is often milder than the one in vapor-diffusion, so that better-quality crystals can be expected.

*High reproducibility / reliability

This device is a spin-off of JAXA-GCF space experiment. High reproducibility and reliability is proven after crystallization over 400 different kinds of proteins.

*Long term stability

Crystals in the capillary are stable for long term. Post-soaking is easy by changing precipitant solution in the cell.

*Acceptable to Membrane proteins

Phase separation due to concentrated detergent in the solution does not occur.Possible to apply to crystalization of membrane proteins.

How to assemble SGT

Product List

Product Name Cat# Quantity

Crystal Tube SGT 3-Cell Type

CFS-MB2004-CRT400 1SET

Crystal Tube SGT 6-Cell Type

CFS-MB2004-CRT404 1SET

SGT Loading Tool w/o Down Controller

CFS-MB2004-CRT300 1SET

SGT Loading Tool with Down Controller

CFS-MB2004-CRT310 1SET
  •  Moreno A et al., Crystal-growth kinetics of protein single crystals along capillary tubes in the gel-acupuncture technique. Acta Crystallogr D Biol Crystallogr. 1999 Feb;55(Pt 2):577-80. PMID: 10089385
  •  McPherson A., Crystallization of Biological Macromolecules, Cold Spring Harbor Lab. Press (1999)
  •  Tanaka H et al, A simplified counter diffusion method combined with a 1D simulation program for optimizing crystallization conditions. J Synchrotron Radiat. 2004 Jan 1;11(Pt 1):45-8. Epub 2003 Nov 28. PMID: 14646131