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.
