Dear experts,
I'm planning to use a EM map to generate a mask for density
modification and also potentially use it in molecular replacement. But
I'm stuck on how to make this EM map to behave now.
The original EM map was a reconstruction from 2D helical tube. The
file was huge (containing several layer of the protein) and ended with
.map. Our computation collaborator had already cut out a dimer, which
is what I'm interested in, and put it into a small unit cell just
slightly bigger than the dimer density. this file is ended with .mrc.
I can open both file with coot and chimera fine. I tried to convert
the dimer map into a .mtz file but when I try to use any of the ccp4
program (sfall, mapman etc), I always get error message on something
like "map and mask grid samplings do not match", "Fatal disagreement
between input info and map header" or "Incorrect sampling grid factors
40 29 45". I'm thinking it may be the unit cell that it is already
in. But as I'm not familiar with Chimera, I couldn't figure out how to
remove it. Also, how to choose and/or specify a proper grid? Any
suggestion on how to make this EM map to work is high appreciated.
Thank you very much!
Best regards,
Fei
Fei LI
Graduate Assistant
310 Biochemistry Building
Department of Biochemistry and Molecular Biology
Michigan State University
East Lansing, MI
48824
