Re: [ccp4bb] Anisotropic data - How to deal with ?

- 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: Symmetry of crystallographic stereographic projections?
From: Ian Tickle I {- dot -} Tickle {- at -} ASTEX-THERAPEUTICS {- dot -} COM
Date: 2007-11-22

Next message:
Subject: Re: Anisotropic data - How to deal with ?
From: Harry Powell harry {- at -} MRC-LMB {- dot -} CAM {- dot -} AC {- dot -} UK
Date: 2007-11-22

Subject: Re: Anisotropic data - How to deal with ?
From: Dirk Kostrewa kostrewa {- at -} LMB {- dot -} UNI-MUENCHEN {- dot -} DE
Date: 2007-11-22

Dear Pierre,

there is also a "Diffraction Anisotropy Server" at UCLA that does
some scaling and truncating of anisotropic data, possibly making your
crystallographic life a bit easier ... but I don't have personal
experiences with this approach.
Have a look at http://www.doe-mbi.ucla.edu/~sawaya/anisoscale/

Best regards,

Dirk.

Am 22.11.2007 um 14:43 schrieb Kay Diederichs:

> Pierre Barraud schrieb:
>> Dear all,
>> I am working on a data set which is severely anisotropic, with
>> diffraction limits of 2.6 A along the a* and b* direction but only
>> 3.3 A along the c* direction. I attached a screen shot of the
>> Anisotropic analysis (FALLOFF) output graph from SCALA.
>> My question is : what is the best strategy (or what are the
>> different strategies) in the structure resolution process (from
>> image integration to refinement) to make use of the maximum high
>> resolution information ? Actually, I am a little disorientated by
>> the informations I have collected.
>> Best regards,
>> Pierre
>
> Pierre,
>
> as you found, data integration is not harmed by anisotropy.
>
> The relevant programs for structure solution and refinement (e.g.
> sharp, molrep, phaser, refmac etc.) deal explicitly with
> anisotropy; I don't think there there is a compelling need to do
> something fancy. Others will correct me.
>
> If you _do_ want an anisotropic resolution cutoff, you could use
> sftools. Load all your data (i.e. up to 2.6A) into sftools. Then
> multiply the length of the c axis by a factor of 2.6/3.3 , and let
> sftools delete all those reflections that are beyond 2.6A now. Then
> restore the original c axis and write out the remaining data.
>
> HTH,
>
> Kay
> --
> Kay Diederichs http://strucbio.biologie.uni-konstanz.de
> email: Kay.Diederichs@uni-konstanz.de Tel +49 7531 88 4049 Fax 3183
> Fachbereich Biologie, Universität Konstanz, Box M647, D-78457 Konstanz

*******************************************************
Dirk Kostrewa
Gene Center, A 5.07
Ludwig-Maximilians-University
Feodor-Lynen-Str. 25
81377 Munich
Germany
Phone: +49-89-2180-76845
Fax: +49-89-2180-76999
E-mail: kostrewa@lmb.uni-muenchen.de
*******************************************************

CCP4bb navigation

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

Previous message:
Subject: Re: Symmetry of crystallographic stereographic projections?
From: Ian Tickle I {- dot -} Tickle {- at -} ASTEX-THERAPEUTICS {- dot -} COM
Date: 2007-11-22

Next message:
Subject: Re: Anisotropic data - How to deal with ?
From: Harry Powell harry {- at -} MRC-LMB {- dot -} CAM {- dot -} AC {- dot -} UK
Date: 2007-11-22