Re: [ccp4bb]: High vs. low symmetry

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

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> 
>                         R               R-free
> Start                   34.9            38.4
> After TLS               27.4            31.6
> After restrained        24.7            29.1
> 
> HOWEVER, when I work up my data in p1 with the same cell now having 4
> monomers in the ASU (R-merge 6.0 %) the refinement looks much better
> (monomers positioned with MOLREP):
> 
>                         R               R-free
> Start                   35.8            34.6
> After TLS               29.7            28.7
> After restrained        23.4            24.7
> 


 That Free R is very misleading. You will obviously have pseudo 222
symmetry, and it is essential that the FreeR set retains that pseudo
symmetry. ie you need to work out how to make sure the related
reflections have the same FreeR. There are ways - easy if your P1 cell
is essentially the same as the P222 one - otherwise quite tricky.. 

If the cells are the same you can use CAD to extend the P222 FreeR flags
to outlim sPAC P1, then add the set using cad again to your "P1" data..


Eleanor