Öffnet in neuem Fenster Opens in a new window Öffnet externe Seite Opens an external site Öffnet externe Seite in neuem Fenster Opens an external site in a new window

Joint Research Group Macromolecular Crystallography

Xe,Kr-Noble Gas Derivatization

Usage of the noble gas chamber within the sample preparation laboratory

The noble gas chamber (Fig. 1) is located in the sample preparation laboratory and can be used to produce xenon and krypton noble-gas derivatives of macromolecular crystals to assist in phase determination or to map solvent channels within protein crystals.

Safety

When using the pressurised chamber please follow all safety instructions specified by BESSY-II safety regulations. Please confirm the use of Xe/Kr-pressurised cell in your PX-safety declaration before coming to the beamline.

enlarged view

Fig. 1 The Xenon/Krypton chamber

Materials

  • Only magnetic bases are supported by the cell
  • Cryo dewar with liquid nitrogen
  • Pincers and mini-vial with wick
enlarged view

Fig 2. Mini-vial with wick and pincers

Pre-operation

  • Use the pincers to remove the mini-vial with wick from the chamber
  • Add 100 μl of milliQ water into the mini-vial to allow the liquid to get absorbed into the wick. Verify there is at least 2mm of water in the bottom of the mini-vial
  • Put the mini-vial back into the chamber
  • Raise the plunger and slide it to the left and lower it into the chamber
  • Close the chamber by turning the lock lever and the safety shield. Leave it for app. 30 min to have a moisture saturated chamber
enlarged view

Fig. 3. An overview of the Xenon chamber device

Usage

  • Open the pressure bottle main valve
  • Set to the required pressure on the pressure regulator valve between 20 - 40 bar (maximum).
  • Raise the plunger to the top and attach the metal base with the crystal to the plunger magnet
  • Slide the plunger to the left and lower it into the chamber
  • Close the safety shield and the metal lock lever
  • Now the chamber is ready for pressurisation
  • Turn the 3 way valve to "Apply pressure"
  • Look at the chamber pressure gauge to see the current pressure of the chamber. If the pressure exceeds 40 bar (600 psi), a safety valve behind the instrument will be released with a plop and the crystal will be lost.
  • If necessary further open the "pressure regulator valve " to reach the desired pressure and then close it.
  • After reaching the desired pressure, turn the 3-way valve to "Hold pressure"
  • Wait for the incubation time.
  • After incubation, very slowly, turn the 3-way valve to "Release pressure". You can use the "Rate adjustment" to regulate the pressure release rate.
  • Once the pressure is completely released, unlock the safety shield and chamber lock
  • Raise the plunger, move it to the right and lower it into the pre-aligned vial in the liquid nitrogen
  • Release the metal base with the magnetic release lever on the top.

Notes

  • Please document the use of the chamber in the log book table
  • If the gas bottle is changed, please incubate once without any crystal to prime the system

References