# Constrain receptor ligand

**URL:** <https://gromacs.bioexcel.eu/t/constrain-receptor-ligand/12298>\
**Category:** User discussions\
**Created:** [June 28, 2025, 5:53pm UTC](https://gromacs.bioexcel.eu/t/constrain-receptor-ligand/12298 "2025-06-28T17:53:28Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![jacopo1](https://avatars.discourse-cdn.com/v4/letter/j/13edae/32.png) [@jacopo1](https://gromacs.bioexcel.eu/u/jacopo1)\
**Post date:** [June 28, 2025, 5:53pm UTC](https://gromacs.bioexcel.eu/t/constrain-receptor-ligand/12298/1 "2025-06-28T17:53:28Z")

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GROMACS version:  
GROMACS modification: Yes/No  
How to perform an equilibration with constrain in GROMACS that mantain atom 123 of receptor and atom 45 of ligand at a fixed distance (2.4 Arsmstrong) ? What i have to do ? Thanks