Re: [ccp4bb]: R32 pseudotranslational symmetry in crystal

["Eleanor J. Dodson" <ccp4@ysbl.york.ac.uk>]

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  I was about to write - read Rams paper..

  But first look at the twinning possibility. This is difficult to 
detect if you also have pseudo symmetry, since the pseudo symmetry 
inflates the moments above the expected values, and the twinning will 
depress them. Results can look almost normal
  Eleanor

rams@poori.biochem.uiowa.edu wrote:
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> 
> Please read 
> Carredano, E., Kauppi, B., Choudhury, D., and Ramaswamy, S. (2000) 
> Psuedosymmetry characterisation in the rhombohedral crystal form of 
> naphthalene dioxygenase.  Acta Crystallographica D56: 313-321.
> 
> 
> Will tell you, how to test and correct....
> 
> Rams.
> 
> 
> 
> On Tue, 25 Feb 2003, N.Manoj wrote:
> 
> 
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>>Dear all,
>>          We have a problem in refining a structure in space group R32.
>>The data processed to 2.9A with  overall Rmerge of 5%, 98% completeness
>>and redundancy of 5. AMoRe gave clear solutions for the two expected
>>molecules in the asymmetric unit. The packing looked good,  but the
>>structure could not be refined below 45% R-factor. Electron density for
>>one monomer is good while it is very poor for the other monomer. 
>>The two molecules are identical (same rotation function values) in
>>orientation and are translated by almost 1/2 along the Z axis. I would
>>like to know if there is some way of going about refining this
>>structure.   
>>I remember some discussion about refinement of structures with  pseudo
>>translational symmetry in the ccp4 BB some time back.
>>
>>Thanks in advance
>>manoj
>>
> 
>