# Help Running Simulation of Liposome Fusion

**URL:** <https://gromacs.bioexcel.eu/t/help-running-simulation-of-liposome-fusion/4424>\
**Category:** User discussions\
**Tags:** mdp-parameters, mdrun\
**Created:** [July 6, 2022, 2:38pm UTC](https://gromacs.bioexcel.eu/t/help-running-simulation-of-liposome-fusion/4424 "2022-07-06T14:38:36Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![vgopal](https://avatars.discourse-cdn.com/v4/letter/v/c68b51/32.png) [@vgopal](https://gromacs.bioexcel.eu/u/vgopal)\
**Post date:** [July 6, 2022, 2:38pm UTC](https://gromacs.bioexcel.eu/t/help-running-simulation-of-liposome-fusion/4424/1 "2022-07-06T14:38:36Z")

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GROMACS version: 2020.1  
GROMACS modification: No  
Hi all,  
I recently posted a thread asking for help in starting an MD simulation of DPPC lipid liposomes. I created the liposome using Packmol to get a pdb file of a liposome with water molecules inside of it. I then used “gmx insert-molecules” to create a GROMACS environment with water as a solvent and two liposomes. I am unsure of how to actually run the simulation now that I have the environment set up. I am aware I need to use “gmx grompp” and take the output from that into “gmx mdrun”. However I am unsure of how to get the topology (.top) or parameter defining files (.mdp) in order to run “grompp” and then “mdrun”. I am very new to GROMACS, and any help in how I could actually run a simulation of the liposomes would be greatly appreciated.  
Thank you,  
Varun Gopal