[ccp4bb] precipitation of the protein in crystallisation solution

- Protein crystallography

Main steps:

- Protein purification
- Crystallisation

Special:

- Programs for crystallography
- X-ray detectors

Basic tutorials:

   - Chemistry
   - Protein
   - Peptide
   - Amino Acids

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- CCP4BB

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: solvent mask with refmac
From: Ed Pozharski epozh001 {- at -} UMARYLAND {- dot -} EDU
Date: 2009-06-02

Next message:
Subject: Re: solvent mask with refmac
From: Clemens Vonrhein vonrhein {- at -} GLOBALPHASING {- dot -} COM
Date: 2009-06-02

Subject: precipitation of the protein in crystallisation solution
From: peter hudson peter {- dot -} hudson {- dot -} peter {- at -} GMAIL {- dot -} COM
Date: 2009-06-02

Hello all

I am working on small protein-protein complex of 10 kDa each component.Among
these complex one of the partner known to be highly

flexible but in complex they are suppose to be well structured and from a
tight complex . I am trying to crystallise this complex. When i add the
protein in crystallisation solution it precipitates immediately in the
crystallisation drop and make slightly yellowish precipitate in most of the
consitions (90%). Conditions in which this proteins either doesnot
precipitate or precipitate with slight delay are either have PEG or Tris-cl
Ph=8.5 buffer. Even the condition which have amm. sulphate like precipitants
and Tris pH=8.5 as a buffer, it precipitates immediately. I am using protein
concentration of 15 mg per ml in buffer Tris-cl Ph=8.0, 100mM NaCl and 1%
Glycerol. This protein forms a slimy yellow deposition on the membrane
surface of the centricon while concentration of the protein.Can any one
suggest what could be the problem under this scenario? suggestions to avoid
the precipitaion of the protein under crystallisation condition as well as
to avoid the slimy deposition fromation on the bed of membrane of the
centricon. I will highly appreciate the comments.

I would also like to know even the comments about the crystallisation
trouble associated with the unstructured or flexible proteins.

Thanks in advance

Regards

peter

CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: solvent mask with refmac
From: Ed Pozharski epozh001 {- at -} UMARYLAND {- dot -} EDU
Date: 2009-06-02

Next message:
Subject: Re: solvent mask with refmac
From: Clemens Vonrhein vonrhein {- at -} GLOBALPHASING {- dot -} COM
Date: 2009-06-02