Re: [ccp4bb] how to improve resolution

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

Previous message:
Subject: Re: HKL-MTZ conversion
From: Frank von Delft frank {- dot -} vondelft {- at -} SGC {- dot -} OX {- dot -} AC {- dot -} UK
Date: 2010-02-05

Next message:
Subject: Re: HKL-MTZ conversion
From: Tim Gruene tg {- at -} SHELX {- dot -} UNI-AC {- dot -} GWDG {- dot -} DE
Date: 2010-02-05

Subject: Re: how to improve resolution
From: Enrico Stura estura {- at -} CEA {- dot -} FR
Date: 2010-02-05

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: Re: HKL-MTZ conversion
From: Frank von Delft frank {- dot -} vondelft {- at -} SGC {- dot -} OX {- dot -} AC {- dot -} UK
Date: 2010-02-05

Next message:
Subject: Re: HKL-MTZ conversion
From: Tim Gruene tg {- at -} SHELX {- dot -} UNI-AC {- dot -} GWDG {- dot -} DE
Date: 2010-02-05