I'm trying to built a protein with 4 identical chains using the
symmetry restrain to CA atoms as section "2.2.11 Building multi-chain
models with symmetry" from modeller 9v7 manual.
...
The problem is that the program stops and the following error message
appears at the shell:
self.restraints.symmetry.append(symmetry(s1, s2, s3, s4, 1.0))
TypeError: __init__() takes exactly 4 arguments (6 given)
Just like the error message says, you cannot create a symmetry element
that contains 4 selections. As in the example, it can only contain 2
selections; it is a pairwise restraint. So you would need to restrain
each pair (s1-s2, s2-s3 and s3-s4) individually.