Crystallization apparatus: Crystal-Tube GT-R

Crystal-Tube GT-R is a simple, easy to use, counter-diffusion-based, capillary crystallization kit that permits gentle crystal growth from very small amounts of protein. Using capillaries of different diameters, users can rapidly optimize crystallization conditions for X-ray diffraction data collection.

Crystal-Tube GT-R is a simple, easy to use, protein crystallization kit that exploits counter-diffusion to grow crystals in a capillary for X-ray diffraction data collection. The kit uses capillaries of different diameters for optimizing crystallization conditions. It was developed by the Japan Space Utilization Promotion Center and Maruwa Foods and Biosciences Inc., subcontracted by the Japan Aerospace Exploration Agency (JAXA) in a series of protein crystallization experiments performed from 2002 to 2006. It is marketed under a licensing agreement with JAXA [Patent: 4354457(JP) 7531037(US)] (1).

A schematic of the apparatus can be found in the User’s Manual. A piece of gel-tubing (gel-tube) is attached to the end of a capillary filled with a protein solution. The capillary/gel-tube assembly is placed into a test tube containing a reservoir solution. In a process is called “counter-diffusion”, protein solutions and reservoir solutions diffuse in opposite directions through the gel-tube, permitting formation of opposing concentration gradients of precipitant and protein in a single capillary. The gel-tube works as a diffusion barrier promoting gentle crystallization. This apparatus permits exploration of a wide range of crystallization conditions in a single experiment, increasing the possibility and reproducibility of obtaining high-quality crystals in a single experiment as compared to conventional batch and vapor-diffusion methods.

Advantages of Crystal-Tube GT-R:


• Requires only small amounts of protein sample:
  
  • 2μl (for optimization)
  
  • 10μl (for X-ray diffraction experiment)
  
  

• Favorable crystallization timing can be controlled by:
  
  • Length of the gel-tube
  
  • Amount of protein solution in a capillary
  
  • Concentrations of protein and precipitant solutions
  
  

• Easy set-up:
  
  • gel-tubing promotes easy assembly of Crystal-Tube
  
  

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

• Easy post-soaking:
  
  • Post-soaking, a common technique for binding ligands to protein molecules in a crystal, is achieved by simply exchanging the precipitant solution in the test tube to a ligand-containing solution
  
  

• Long-term crystal stability:
  
  • Crystals produced in the capillary are stable for a long time
  
  

• Membrane protein crystallization:
  
  • Phase separation due to concentrated detergent in the solution does not occur
  
  

• Optimization of crystallization conditions:
  
  • A 1-dimensional simulation program (optional) can assist in estimating the time-course of solution conditions in the capillary.
  
  


References


1. Tanaka, H. et al., J. Synchrotron Rad. (2004). 11, 45-48.