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Re: [ccp4bb]: bulk solvent corrected fo-fc map?



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If you are using refmac5 you need to use in FFT F1-FWt ( the SigmaA 
weighted 2Fo-DFc term) and PHWT ( no PHIC, no W=FOM).
  For a difference map use F1-DELFWT PHI=PHDELWT

Or you could ask for maps to be output from the GUI in XtalView format - 
in fact it gives you a *.phs ready for calculating each map.

Eleanor
PS - can you tell us if this fixes your problem? And what resolution 
your data reaches?
There might also be differences in the scaling used which can be 
important at lower reslns

Mark DePristo wrote:

> ***  For details on how to be removed from this list visit the  ***
> ***          CCP4 home page http://www.ccp4.ac.uk         ***
>
> Hi,
>
> I've been struggling to create reasonable fo-fc maps with CCP4.  The 
> fo-fc maps created directly with xfit in xtalview are very nice, 
> clearly highlighting poorly placed sidechain atoms on the protein 
> surface.  However, the fo-fc maps calculated with CCP4's fft from the 
> equivalent mtz FP, FC, and PHIC are poor and impossible to interpret.  
> Interestingly, the xfit fo-fc maps are very similar to the CCP4 maps 
> when xfit's fft the bulk solvent correction is disabled.
>
> I'd love to enable bulk solvent correction in my CCP4 maps calculated 
> by fft, but I've been unable to figure out how to do this.  I've tried 
> the DELFT and PHDELFT labels output by refmac, but these maps are also 
> poor.  Is there any way to produce bulk solvent corrected difference 
> maps from the command line in CCP4?
>
> Thanks,
>
> Mark
>
> Mark DePristo
> Ph.D. Candidate
> Dept. of Biochemistry
> Cambridge University
> mdepristo@cryst.bioc.cam.ac.uk
> http://www-cryst.bioc.cam.ac.uk/~mdepristo/
>
>
>