# Protein-ligand Molecular dynamics using gromacs
**URL:** https://ask.bioexcel.eu/t/protein-ligand-molecular-dynamics-using-gromacs/1432
**Category:** GROMACS
**Created:** [February 15, 2019, 5:02am UTC](https://ask.bioexcel.eu/t/protein-ligand-molecular-dynamics-using-gromacs/1432 "2019-02-15T05:02:50Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@harshitha](https://ask.bioexcel.eu/u/harshitha)
#### Post date: [February 15, 2019, 5:02am UTC](https://ask.bioexcel.eu/t/protein-ligand-molecular-dynamics-using-gromacs/1432/1 "2019-02-15T05:02:50Z")
How to prepare hybrid forcefield in case of protein ligand simulation
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### Author:  [@acmnpv](https://ask.bioexcel.eu/u/acmnpv)
#### Post date: [March 12, 2019, 10:11am UTC](https://ask.bioexcel.eu/t/protein-ligand-molecular-dynamics-using-gromacs/1432/2 "2019-03-12T10:11:46Z")
Hello and sorry for the long delay before answering.
For simulating ligands that have not been parameterized for your force field, you need to perform the step of obtaining the parameters yourself.
Some hints can be found here ([http://manual.gromacs.org/documentation/current/user-guide/faq.html#parameterization-and-force-fields](http://manual.gromacs.org/documentation/current/user-guide/faq.html#parameterization-and-force-fields)) and here ([http://manual.gromacs.org/documentation/current/how-to/special.html#parameterization-of-novel-molecules](http://manual.gromacs.org/documentation/current/how-to/special.html#parameterization-of-novel-molecules)).
Please be aware that the process of preparing a new residue for a simulation and its validation can be time consuming and difficult, even for expert users.
Cheers
Paul