Re: [ccp4bb] Mosflm : data process of crystal with huge unit cell

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

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Subject: Re: Mosflm : data process of crystal with huge unit cell
From: "Winter, G (Graeme)" g {- dot -} winter {- at -} DL {- dot -} AC {- dot -} UK
Date: 2008-05-22

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Subject: Re: Mosflm : data process of crystal with huge unit cell
From: Marian Szebenyi dms35 {- at -} CORNELL {- dot -} EDU
Date: 2008-05-22

Franciso,

Mosflm does not do a good job refining mosaicity for narrow oscillation
ranges such as you used. I would set the mosaicity to a value that
predicts a number of spots that matches what you actually see and keep
it fixed. Depending on how large your mosaicity actually is, mosflm may
also have trouble refining other parameters - it works best when
reflections do not extend over more than 2 or 3 frames.

Your best bet is probably to use XDS, which is designed for narrow
oscillation ranges.

Marian Szebenyi
MacCHESS

fenguita@ITQB.UNL.PT wrote:
> Dear All
>
> I am processing data from a crystal for a large macromolecular complex
> with mosflm. Cell dimensions are around 120 x 150 x 650, with a p222
> spacegroup. To avoid overlaps, we have collected data with a oscillation
> of 0.1 degrees.
>
> When I try to process the data with mosflm, mosaicity decreases along the
> processing to a very low values (0.05 to 0.1 depending on the images). The
> result is that I miss a lot of spots from the images.
>
> I would appreciate any help regarding :
>
> 1.- What's is the best strategy to process such a dataset ?
> 2.- Which are the critical parameters in mosflm to avoid these problems,
> and how to modify them ?
> 3.- and finally, can I use this data or your advice is to try to get
> crystals in a different spacegroup ?
>
> Many thanks
>
> Best regards
>
> Francisco
>
>
>
> -----------------------------------------
> Francisco J. Enguita, Ph.D.
> Macromolecular Crystallography Laboratory
> ITQB
> EAN, Av. da República
> 2781-901 Oeiras
> Portugal
> Phone : +351-21-4469663
> Fax : +351-21-4433644
> E-mail : fenguita@itqb.unl.pt
> -----------------------------------------
>

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

Previous message:
Subject: Re: Mosflm : data process of crystal with huge unit cell
From: "Winter, G (Graeme)" g {- dot -} winter {- at -} DL {- dot -} AC {- dot -} UK
Date: 2008-05-22

Next message:
Subject: Microscope & camera for taking crystal picture
From: aida baha aidabaha {- at -} GMAIL {- dot -} COM
Date: 2008-05-22