Team:Wageningen UR/Protocol/DialysisHepB

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Dialysis of the VLPs

  • This protocol is based on the CCMV VLP formation protocol. We made adjustments because HepBcAg has a different pH at which the particle is stable. Besides, the number of dialysis steps is reduced and only 1 buffer is needed for the dialysis.</li>

    Reagents & Materials

    Reagents:

    • Formation Buffer
    • Formation Buffer + 8M urea

    Materials:

    • Pipettes + pipettepoints
    • Greinertubes
    • Dialysis tubing
    • Vortex
    • French Press
    • Centrifuge for Greiner tubes
    • Sorval or a similar centrifuge
    • Coldroom

    Procedure

    The temperature of the VLP’s is very important. All the work should be done in the cold room (4°C) and the used tubes have to be on ice.

    1. Resuspend the cells in 5 mL of Disassembly buffer
    2. Disrupt the cells by french press, cell pressure: 1000
    3. Add Disassembly buffer to 25 mL total volume
    4. Centrifuge the lysate until the insoluble fraction is pelleted – 4°C, 4700 rpm, 18 min
    5. Remove the supernatant completely and dissolve the pellet in 10 mL of cold Disassembly buffer containing 8 M urea (about 10-15 min). Vortex the pellet to easily resuspend the while cooling on ice. Do not allow the buffer to heat up above 25°C
    6. Allow the pellet to dissolve for 2-5 minutes
    7. Dilute the 10 mL of 8 M urea/ Disassembly buffer with 15 mL Disassembly buffer. If crystals form, the batch should be discarded
    8. Pellet everything that is not dissolved by centrifuging at 15000 rpm at 4°C for 15 minutes (Sorvall ultracentrifuge in the basement)
    9. Transfer the supernatant to a clean 50 mL Greiner tube
    10. Prepare a piece of dialysis tubing with a large diameter by soaking it in cooking demiwater until it opens up
    11. Put a tight knot on one side and fill the tubing with the supernatant
    12. Knot the tube on the other side leaving a small air bubble inside
    13. Dialyse the tube (about 25 mL volume) against 1x Dialysis buffer for 4 hours or overnight
    14. Dialysis is performed 6 times against 1x Formation(4h per dialysis, or overnight)


    Continue further for HepB formation