[ccp4bb] refinement of half molecules

- Protein crystallography

Main steps:

- Protein purification
- Crystallisation

Special:

- Programs for crystallography
- X-ray detectors

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   - Chemistry
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   - Amino Acids

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

Previous message:
Subject: Re: Reading the old literature / truncate / refinement programs
From: Frank von Delft frank {- dot -} vondelft {- at -} SGC {- dot -} OX {- dot -} AC {- dot -} UK
Date: 2008-10-03

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Subject: Re: Reading the old literature / truncate / refinement programs
From: "Ian J {- dot -} Tickle" i {- dot -} tickle {- at -} ASTEX-THERAPEUTICS {- dot -} COM
Date: 2008-10-03

Subject: refinement of half molecules
From: Andreas_Förster docandreas {- at -} GMAIL {- dot -} COM
Date: 2008-10-03

Hey all,

I have a structure where two (identical) half molecules occupy one unit
cell but are shifted by half a unit cell translation. I would like to
refine them concurrently with global occupancy for each protein fixed to
1/2 initially (maybe relax that later). Is that possible in refmac and
how? How about phenix, CNS?

Thank you.

Andreas

Some more details for those interested in crystal pathologies. A
fraction of the unit cells making up the crystal are shifted by half a
unit cell translation in a statistic manner (peak in native Patterson at
0.5z). The structure was solved by MR with one molecule per au but
doesn't refine. There is good density for the MR solution, but the
solution shifted by 1/2 z fits the density nearly as well.

--
Andreas Förster, Research Associate
Paul Freemont & Xiaodong Zhang Labs
Department of Biochemistry, Imperial College London

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