Re: [ccp4bb] how to improve resolution

- Protein crystallography

Main steps:

- Protein purification
- Crystallisation

Special:

- Programs for crystallography
- X-ray detectors

Basic tutorials:

   - Chemistry
   - Protein
   - Peptide
   - Amino Acids

Xtal community:

- CCP4BB

CCP4bb navigation

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

Previous message:
Subject: Re: how to improve resolution
From: Frederic VELLIEUX frederic {- dot -} vellieux {- at -} ORANGE {- dot -} FR
Date: 2010-02-05

Next message:
Subject: Re: HKL-MTZ conversion
From: Phil Evans pre {- at -} MRC-LMB {- dot -} CAM {- dot -} AC {- dot -} UK
Date: 2010-02-05

Subject: Re: how to improve resolution
From: Ganesh Natrajan natrajan {- at -} EMBL {- dot -} FR
Date: 2010-02-05

Hi Rui,

In addition to what Fred has advised, you could also try
varying other parameters like temperature and protein concentration. 32 %
is

a very high concentration of precipitant. Maybe you could try using a
bigger PEG (like PEG 8000), at a lower concentration. It worked for me

once. Also, if ever you are at ESRF, you could try the crystal
dehydrating device.

Ganesh

**********************************************
The boast of heraldry, the
pomp of power,
And all that beauty, all that wealth e'er gave,
Awaits alike
the inevitable hour.
The paths of glory lead but to the grave.

-Thomas
Gray, Elegy Written in a Country
Churchyard
**********************************************

On Thu, 4 Feb
2010 23:39:14 -0500, 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. 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.

--

CCP4bb navigation

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

Previous message:
Subject: Re: how to improve resolution
From: Frederic VELLIEUX frederic {- dot -} vellieux {- at -} ORANGE {- dot -} FR
Date: 2010-02-05

Next message:
Subject: Re: HKL-MTZ conversion
From: Phil Evans pre {- at -} MRC-LMB {- dot -} CAM {- dot -} AC {- dot -} UK
Date: 2010-02-05