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: HKL-MTZ conversion
From: Sylvia Fanucchi Sylvia {- dot -} Fanucchi {- at -} WITS {- dot -} AC {- dot -} ZA
Date: 2010-02-05

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

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

Hi Rui,

Several things you can do:

1 - use a beam line with extremely high flux (here at ESRF it would be ID23-1 and ID-29) so that the crystal(s) give
their uttermost diffraction before they notice that they are being hit by something "nasty" --- you usually get only
very few high resolution diffraction frames doing that;

2 - use the additive screens that are available from several vendors. Blind screen, and you only select thos
conditions that do not have the protein precipitate but give you crystals (few of them per crystallisation droplet),
and test them for diffraction quality (we've had lots of success with this approach at IBS/LBM);

3 - more extensive screening of initial conditions to discover new hits.

Fred.

> Message du 05/02/10 05:39
> De : "rui"
> A : CCP4BB@JISCMAIL.AC.UK
> Copie Ã :
> Objet : [ccp4bb] how to improve resolution
>
> 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: HKL-MTZ conversion
From: Sylvia Fanucchi Sylvia {- dot -} Fanucchi {- at -} WITS {- dot -} AC {- dot -} ZA
Date: 2010-02-05

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