Like Herman, it was not apparent to me what exactly you want wanted.

If you want a map that covers only [1] or excludes [2] a particular atom selection then you can do that in Coot. 

Extensions -> Maps... -> Mask Map by Atom Selection,

e.g. to show only the "A" chain, use an atom selection of "//A".

You can then export the map using:

Extensions -> Maps... -> Export Map  
or
Extensions -> Maps... -> Export Local Map Fragment...

If you really want structure factors from that then you can use sfall (MODE SFCALC MAPIN).

Paul.

[1] use mask inversion
[2] don't use mask inversion


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From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of zhang yu
Sent: Sunday, February 19, 2012 11:47 PM
To: [log in to unmask]
Subject: [ccp4bb] FFT map coefficients only for certain chains

Dear CCP4ers,

Is that possible to generate map coefficients only for certain chains? For example, I have two chains, A and B, and I would like to output a map file only contains coefficients for chain A. The "isomesh" command in Pymol could generate similar images. But my purpose is not for presentation, I need a map file only contains coefficient for certain chains. 

In the interface of "FFT" tool in Phenix or CCP4, there is an option to include a PDB file and define atom selections. It describe that "If a PDB is supplied, the output map will cover the model plus a buffer on all sides. The atom selection parameters can be used to specify a smaller region" . If I define the selection as chain A when I run the FFT, the output map still covers a rectangular block containing chain A, instead of regions only surrounding chain A.

Thanks.

Yu

 



--
Yu Zhang
HHMI associate
Waksman Institute, Rutgers University
190 Frelinghuysen Rd.
Piscataway, NJ, 08904