But, if you convert to structure factors and recalculate the map in a different cell,
the features will be "stretched" to fill the cell, which I take it is the original problem.
I found Kleywegt's RAVE package very convenient for doing this,
but i believe the functionality is now available in
ccp4 mapmask and maprot programs.
The Phaser Wiki has a page with instructions
for cutting out electron density within a mask,
and putting it in a large P1 cell for use as a molecular
replacement model. Perhaps you could modify that to achieve
your aims.
http://www.phaser.cimr.cam.ac.uk/index.php/Using_Electron_Density_as_a_Model
eab
On 05/20/2014 03:07 AM, [log in to unmask] wrote:
> Dear Niu,
>
> Provided you have a complete asymmetric unit (unit cell in P1), you could also convert this map to
> structure factors and manipulate those, e.g. with sftools. To calculate structure factors you could use
> sfall and also clipper has utilities to convert a map to structure factors.
>
> Best,
>
> Herman
>
> *Von:*CCP4 bulletin board [mailto:[log in to unmask]] *Im Auftrag von *Niu Tou
> *Gesendet:* Montag, 19. Mai 2014 23:25
> *An:* [log in to unmask]
> *Betreff:* [ccp4bb] map manipulation questions
>
> Dear All,
>
> I have a ccp4 format map file in P1 spacegroup, I would like to manipulate it in several ways:
>
> 1. enlarge the cell dimension . When I tried "CELL" keyword in MAPMAN, the density scaled up together
> with the cell dimension. Does anybody know how to do it without changing the density?
>
> 2. Change the space group to P2.
>
> 3. Move the density away from its original place, i.e. apply a translocation vector to it.
>
> Does anybody know the answers? Thanks in advance!
>
> Regards,
>
> Niu
>
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