Re: [ccp4bb] how to improve resolution

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

Previous message:
Subject: HKL-MTZ conversion
From: Marcus Winter Marcus {- dot -} Winter {- at -} OXFORD-DIFFRACTION {- dot -} COM
Date: 2010-02-05

Next message:
Subject: how to improve resolution
From: Marcus Winter Marcus {- dot -} Winter {- at -} OXFORD-DIFFRACTION {- dot -} COM
Date: 2010-02-05

Subject: Re: how to improve resolution
From: rui ruisher {- at -} GMAIL {- dot -} COM
Date: 2010-02-05

Hi, Thanks all for the good suggestions, I just attached two images that
show my crystals, maybe you'll see new problems with the conditions. Thanks
again.

On Fri, Feb 5, 2010 at 7:43 AM, Enrico Stura wrote:

> On Fri, 05 Feb 2010 05:39:14 +0100, rui wrote:
>
> Hi, All,
>>
>> We are trying to crystallize a protein and found some initial hit in the
>> following conditions,
>>
>> pH 4.8, 0.2 M AS or some other salts ( NaCl,LiCl, MgCl2 ), 32% PEG4000 or
>> PEG3350 ). However the quality of the crystal is not so great,some of them
>> look like needle cluster(very long in length), some of them look like
>> multi-crystals or hollow inside.
>>
> Such growth problems are likely due to the quality of the protein solution.
> Changes in precipitant concentrations are likely to be ineffective. Try
> ion exchange purification.
>
>
> We tried to optimize the pH and PEG and
>> tested one that diffracts at 2.9A. For the next, how to improve
>> resolution?Any suggestions? Even mutate the protein to get a high
>> resolution
>> is ok, generally what kind of mutation would make proteins crystallize
>> better? Thanks.
>>
> It is not mutations that will improve diffraction, it is small changes
> in crystal contacts.
> The Discussion section from:
>
> http://pubs.acs.org/cgi-bin/article.cgi/cgdefu/2007/7/i11/html/cg700698d.html
>
> may help.
>
> Enrico
>
> --
> Enrico A. Stura D.Phil. (Oxon) , Tel: 33 (0)1 69 08 4302 Office
> Room 19, Bat.152, Tel: 33 (0)1 69 08 9449 Lab
> LTMB, SIMOPRO, IBiTec-S, CEA Saclay, 91191 Gif-sur-Yvette
> Cedex FRANCE http://www-dsv.cea.fr/en/ibitecs/82
> http://www.chem.gla.ac.uk/protein/mirror/stura/index2.html
> e-mail: estura@cea.fr Fax: 33 (0)1 69 08 90 71
>

CCP4bb navigation

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

Previous message:
Subject: HKL-MTZ conversion
From: Marcus Winter Marcus {- dot -} Winter {- at -} OXFORD-DIFFRACTION {- dot -} COM
Date: 2010-02-05

Next message:
Subject: how to improve resolution
From: Marcus Winter Marcus {- dot -} Winter {- at -} OXFORD-DIFFRACTION {- dot -} COM
Date: 2010-02-05