# Error in docked complex simulation **URL:** \ **Category:** User discussions\ **Tags:** forcefield, mdrun, analysis-tools, simulation-setup\ **Created:** [April 20, 2025, 12:50pm UTC](https://gromacs.bioexcel.eu/t/error-in-docked-complex-simulation/11957 "2025-04-20T12:50:04Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Ikshika](https://avatars.discourse-cdn.com/v4/letter/i/dc4da7/32.png) [@Ikshika](https://gromacs.bioexcel.eu/u/Ikshika)\ **Post date:** [April 20, 2025, 12:50pm UTC](https://gromacs.bioexcel.eu/t/error-in-docked-complex-simulation/11957/1 "2025-04-20T12:50:04Z")
GROMACS version: 2023 GROMACS modification: Yes/No I have used docked peptide drug complex for simulation in gromacs. i have attached the picture of docked complex below. i generated the topolgy files for drug using acpype and then edited the topology file and added the parameters of my drug into it. however after the simulation of 50ns my drug has distorted it’s shape and drifted away from my peptide. I have attached pictures below. Kinldy help. I am unable to figure out the error. ![Docked complex](https://europe1.discourse-cdn.com/flex017/uploads/bioexcel1/original/2X/8/8175af32c2cb11b6f8267547023fe27c7927407e.png) ![WhatsApp Image 2025-04-20 at 6.18.04 PM](https://europe1.discourse-cdn.com/flex017/uploads/bioexcel1/original/2X/b/b2b4de51f381316ce7d5c97d9e1a549cd700cb75.jpeg) the second image is after simulation of 50 ns. This is a snapshot at 10 ns. ---
**Author:** ![Ashutosh](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/ashutosh/32/2587_2.png) [@Ashutosh](https://gromacs.bioexcel.eu/u/Ashutosh)\ **Post date:** [April 22, 2025, 3:48am UTC](https://gromacs.bioexcel.eu/t/error-in-docked-complex-simulation/11957/2 "2025-04-22T03:48:13Z")
Please check if the drug you used is in 3d format or 2d format if its 2d convert it into 3d maybe it can help