[modeller_usage] symmetric hexamer

Hello,

we are trying to build a symmetric hexamer of a 735 aa protein molecule. Modelling the monomer works without problems. For the hexamer, we have generated the hexameric template and replicated the target sequence in the alignment file accordingly. This works flawlessly, as well.
However, if we insert these symmetry retraints (adopted from the example in the manual)

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# Override the 'special_restraints' and 'user_after_single_model' methods:
class MyModel(automodel):
   def special_restraints(self, aln):
       # Constrain the A and B chains to be identical (but only restrain
       # the C-alpha atoms, to reduce the number of interatomic distances
       # that need to be calculated):
       s1 = selection(self.chains['A']).only_atom_types('CA')
       s2 = selection(self.chains['B']).only_atom_types('CA')
       s3 = selection(self.chains['C']).only_atom_types('CA')       
       s4 = selection(self.chains['D']).only_atom_types('CA')       
       s5 = selection(self.chains['E']).only_atom_types('CA')       
       s6 = selection(self.chains['F']).only_atom_types('CA')       
       self.restraints.symmetry.append(symmetry(s1, s2, s3, s4, s5, s6, 1.0))
   def user_after_single_model(self):
       # Report on symmetry violations greater than 1A after building
       # each model:
       self.restraints.symmetry.report(1.0)
-------------------------------------------

leaving both alignment and template files untouched, then the program stops with the following error:

-------------------------------------------
Traceback (most recent call last):
  File "get-model2.py", line 42, in ?
    a.make()                           # do homology modeling
  File "/usr/local/modeller_9v4/modlib/modeller/automodel/automodel.py", line 98, in make
    self.homcsr(exit_stage)
  File "/usr/local/modeller_9v4/modlib/modeller/automodel/automodel.py", line 436, in homcsr
    self.mkhomcsr(selection(self), aln)
  File "/usr/local/modeller_9v4/modlib/modeller/automodel/automodel.py", line 524, in mkhomcsr
    self.special_restraints(aln)
  File "get-model2.py", line 23, in special_restraints
    self.restraints.symmetry.append(symmetry(s1, s2, s3, s4, s5, s6, 1.0))
TypeError: __init__() takes exactly 4 arguments (8 given)
-------------------------------------------

We are a bit lost here :( Which init call is the message referring to?
Any ideas how to resolve this?

Oliver





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