# Symmetry restraints

**URL:** <https://gromacs.bioexcel.eu/t/symmetry-restraints/672>\
**Category:** User discussions\
**Created:** [August 16, 2020, 2:57pm UTC](https://gromacs.bioexcel.eu/t/symmetry-restraints/672 "2020-08-16T14:57:10Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![genie](https://avatars.discourse-cdn.com/v4/letter/g/dfb087/32.png) [@genie](https://gromacs.bioexcel.eu/u/genie)\
**Post date:** [August 16, 2020, 2:57pm UTC](https://gromacs.bioexcel.eu/t/symmetry-restraints/672/1 "2020-08-16T14:57:11Z")

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Hello,

I wonder is there a convenient way to implement symmetry restraints (e.g. for multi-chain proteins) in GROMACS?  
I understand that the actual symmetry groups are probably not supported, but I guess it should be possible at least to restrain the in-molecule interatomic distances and/or dihedral angles to their values in an equivalent molecule (like MODELLER does [https://salilab.org/modeller/9.24/manual/node113.html](https://salilab.org/modeller/9.24/manual/node113.html)) or to their averaged values (similar to what was done here with NAMD [https://onlinelibrary.wiley.com/doi/abs/10.1002/prot.22618](https://onlinelibrary.wiley.com/doi/abs/10.1002/prot.22618)).  
The latter option seems to be possible using ensemble averaging, but some examples would be very useful!

Thank you