Symmetry restraints

Symmetry restraints can be used to favor symmetry of a complex. In contrast to symmetry constraints, the restraints can be violated and only favor symmetry, with “strength” dependent on their user-defined weight.

They can be used when expect some deviations from a perfect symmetry.

To use restraints:

1. Set add_symmetry_restraints = True in params.py

2. Optionally, set symmetry_restraints_weight = <some value> in params.py

3. Define symmetry axes transformations as in Defining symmetry

4. Define which components (subunits or specific regions of a subunit) should be restrained as in the Applying symmetry

5. Add sym_restraints to the scoring function in params.py, for example:

   scoring_functions = {
       'score_func_lowres': {
           'restraints': [
               'xlink_restraints',
               'conn_restraints',
               'ev_restraints_lowres',
               'FitRestraint',
               'sym_restraints'
           ]
       }
   }
   

Note

You can use both symmetry constraints and restraints, applying constraints to some subunits or regions, and restraints to others!