I'm sorry but I'm a little confused by your question.  If your map
already has four-fold symmetry why can't you simply build your model
once in one quarter of the map?  What do you hope to change by
specifying that the space group is P4?

Dale Tronrud

On 5/18/2017 10:06 PM, Qingfeng Chen wrote:
> Hi,
>
> I have an EM map of a tetrameric protein. It was painful to work with
> this map since it is in P1 spacegroup, although 4-fold symmetry was
> already applied during map reconstruction.
>
> I noticed that people used MAPMAN to transform spacegroup, however, it
> seems not working for me. The map remained in P1 spacegroup afterwards.
>
> I used mtz file converted from .mrc and the tetrameric protein model as
> input and choose "run fft to generate simple map". I also specified
> "output map in ccp4 format to cover all atoms in pdb". In "infrequently
> used options", I input P4 in "generate map in spacegroup". Everything
> else was left as default.
>
> Any suggestions will be appreciated.
>
> Thanks!