Re: [ccp4bb] detergent crystals

- Protein crystallography

Main steps:

- Protein purification
- Crystallisation

Special:

- Programs for crystallography
- X-ray detectors

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

Previous message:
Subject: Re: detergent crystals
From: Leigh Rees leigh {- dot -} rees {- at -} OXFORD-DIFFRACTION {- dot -} COM
Date: 2009-08-04

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Subject: Beamline Scientist PROXIMA 2
From: SHEPARD William william {- dot -} shepard {- at -} SYNCHROTRON-SOLEIL {- dot -} FR
Date: 2009-08-04

Subject: Re: detergent crystals
From: Jose Antonio Cuesta Seijo jose {- at -} KEMI {- dot -} KU {- dot -} DK
Date: 2009-08-04

Hi Parveen.

DDM crystals can look a bit like that. Like a pencil that has been
sharpened from both ends until there is very little pencil left, but often
the ends are flatter than that. You can get tons of these (also with DM) in
conditions with medium weight PEGs. Of course many proteins will also
crystallize as hexagonal rods with PEGs :-)
I'll take this chance to shre a thought with the community. When we say
"contains x% of detergent y", are we sure of what there is in the protein
stock? Most membrane protein stocks for crystallization will undergo a
concentration step in a filter, and the membrane proteins themselves can be
excellent detergent concentrators. For example, 0.05% DDM is about 1 mM
DDM, hardly enough to make a belt around proteins that are 100 uM or
higher.
Do people measure how much detergent there really is in the final
crystallization stock? It doesn't seem to get published, instead the
concentration in the last purification step is often mentioned.

Jose.

"Parveen Goyal" wrote:
> Hi All,
>
> I got some hexagonal crystals in one of my crystal condition. The protein
is
> a membrane protein and contains 0.05% DDM. Has anybody seen DDM crysals
and
> if yes, how do they look like?
>
> thanks in advance
>
> Parveen Goyal
>

--
***************************
Jose Antonio Cuesta-Seijo

Biophysical
Chemistry Group
Department of Chemistry
University of Copenhagen
Tlf:
+45-35320261
Universitetsparken 5
DK-2100 Copenhagen,
Denmark
***************************

CCP4bb navigation

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

Previous message:
Subject: Re: detergent crystals
From: Leigh Rees leigh {- dot -} rees {- at -} OXFORD-DIFFRACTION {- dot -} COM
Date: 2009-08-04

Next message:
Subject: Beamline Scientist PROXIMA 2
From: SHEPARD William william {- dot -} shepard {- at -} SYNCHROTRON-SOLEIL {- dot -} FR
Date: 2009-08-04