Re: [ccp4bb]: problem with refinement

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

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Zhiqiang Lu wrote:
> 
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> 
> Dear All,
> 
> Looking for some help here with the refinement on a small protein
> structure. (does not look like CCP4 related, sorry)
> 
> I was able to fit the AA into the solvent-flipped density map from CNS -
> everything looks just wonderful except for one five-residue loop. However,
> shelxl refinement does not like this model, returning R(free) around 50%
> at 1.8A resolution. Any suggestions, anyone? Thanks very much!
> 
> BTW, does this have anything to do with these two facts: 1) the space
> group is I432; and 2) the model is being refined against Se-Met data
> without merging Friedel mates?
> 
> Z. Lu


 shelxl isnt very happy at 1.8A - why nor use REFMAC or CNS - both
faster and more appropriate at this resolution? 
  Eleanor

> 
> =====
> Zhiqiang Lu,  Graduate Student
> Department of Chemistry & Biochemistry
> University of Arkansas
> Fayetteville, AR 72701
> U.S.A.