EMAN Tutorial
How to do a Reconstruction
Particle with no symmetry
This is the most difficult type of reconstruction to perform. The refinement
procedure is quite robust and capable of working with asymmetrical data.
The difficulty lies in generating a preliminary model to bootstrap the
refinement procedure. Generally it is sufficient to examine a set of particles,
then build a model from 'balls and sticks' which looks like it might be
similar to the actual structure. In reality this model can be quite different
from the true molecule and the refinement procedure will still function.
The problem is, currently EMAN doesn't contain a GUI program for building
such a model. We are working on a program to generate preliminary models
automatically, but it isn't completely functional yet. Currently you'll
have to modify a program to generate an initial model. In the main EMAN
source directory, there is a subdirectory called 'test'. In that directory
are 3 sample programs which create simple 3d models: 'ryr3d.C', 'tri3dg.C'
and 'mk3dgaus.C'. Modify one of these programs to create the model you
wish to start with, then copy it to the name 'tst.c' in the main source
directory. At this point, doing a 'make' will compile this new program.
In the next version, this should be replaced with an automatic procedure.
Generate an initial model as described above. (tst)
Now you should decide if
you want to do CTF correction or not:
No, I'll try the
uncorrected structure first.
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