sadaf iqbal wrote:
> Hello everyone,
>
> Do anybody know the correct procedure for calculating omit map in
> CCP4, if one need to reduce the bias from the Molecular Replacement
> structure. I am confused about the two options, one is fft map
> calculation while the other is OMIT map calculation in Map & Mask
> Utilities window. Which one can be used for omit map?
>
> Regards
>
> Sadaf Iqbal
> PhD Scholar
> ICCBS, University of Karachi, Pakistan.
Hi,
As far as I know there are 2 ways of creating Bhat's OMIT maps within ccp4:
- the program OMIT (not in ccp4i);
- the program sfcheck, with option NOMIT.
Otherwise people sometimes refer to OMIT maps as maps in which a
specific part of the model is removed for the calculation of the phases
used in the computation of the map; the map is then examined in that
area to see if the density for the removed part reappears. There are
many ways of computing such maps (including using a text editor to
remove part of the model, or reset occupancies to 0.0 for the part that
is going to be removed - and including computer programs not in ccp4).
Fred.
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