Re: [ccp4bb] highly soluble proteins

- Protein crystallography

Main steps:

- Protein purification
- Crystallisation

Special:

- Programs for crystallography
- X-ray detectors

Basic tutorials:

   - Chemistry
   - Protein
   - Peptide
   - Amino Acids

Xtal community:

- CCP4BB

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

Previous message:
Subject: Re: needles vs crystals
From: James Pauff pauffjm {- at -} YAHOO {- dot -} COM
Date: 2007-08-07

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Subject: Merging datasets
From: Kianoush Sadre-Bazzaz ksadree {- at -} YAHOO {- dot -} COM
Date: 2007-08-07

Subject: Re: highly soluble proteins
From: M T michelthe {- at -} GMAIL {- dot -} COM
Date: 2007-08-07

First i think that your protein concentration is to low... A common rule is
: protein concentration is good when 50% of your conditions are precipitates
and 50% are clears drops. If most of your drops are clear, i think that you
must increase your protein concentration (a screen from Hampton can help you
for the concentration of your protein: PCT screen).
For your oily bubbles, it often appear when PEG is in the condition, it's
just phase separation.
An other suggestion is that your buffer concentration is too high... If your
buffer is a strong buffer, the conditions buffers can be too weak versus
your 50mM. By the way, real pH in your condition may be something between
the pH of the condition and the pH of the protein sample and not the real pH
of your condition. So you don't have a real access to all the pHs of the
screens.

In summary, reduce your protein sample buffer concentration (to 25 or 10mM)
and increase your protein concentration (to 50, 100 mg/ml or more).

Michel.

CCP4bb navigation

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

Previous message:
Subject: Re: needles vs crystals
From: James Pauff pauffjm {- at -} YAHOO {- dot -} COM
Date: 2007-08-07

Next message:
Subject: Merging datasets
From: Kianoush Sadre-Bazzaz ksadree {- at -} YAHOO {- dot -} COM
Date: 2007-08-07