X-tal protocols

Drops: 3. Precipitated protein.

Protein Detergent Methods Euipment Screen Drops Reference
3. Precipitated protein.

Drop with precipitated protein In the initial screen:

  • If the protein precipitated within 1 day repeat the condition with a lower precipitant concentration.
  • If the heavy precipitate is formed after a few days, the condition does not favor crystallization.
    Evaluate unfavorable condition (pH, precipitant or additive)

  • Drop with precipitated protein

    This is not a good starting point. Protein possibly denatured, judged upon the dark/brown appearence of the precipitate.
    Tip: Dilute the drop with water, if the protein does not dissolve, the protein is probably denatured.

    Drop with protein skin In older drops a skin of denatured protein can appear on the surface of the drop.If the surface has a film that is not wrinkled it could be phase separation.

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