# Fatal error while doing Protein-ligand simulation using GROMACS 2023

**URL:** https://gromacs.bioexcel.eu/t/fatal-error-while-doing-protein-ligand-simulation-using-gromacs-2023/7515
**Category:** User discussions
**Tags:** simulation-setup
**Created:** [October 31, 2023, 11:43am UTC](https://gromacs.bioexcel.eu/t/fatal-error-while-doing-protein-ligand-simulation-using-gromacs-2023/7515 "2023-10-31T11:43:11Z")
**Posts on this page:** 1
**Showing post:** 5

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### Author: ![dlakhan](https://avatars.discourse-cdn.com/v4/letter/d/ecc23a/32.png) [@dlakhan](https://gromacs.bioexcel.eu/u/dlakhan)
#### Post date: [June 18, 2024, 1:52am UTC](https://gromacs.bioexcel.eu/t/fatal-error-while-doing-protein-ligand-simulation-using-gromacs-2023/7515/5 "2024-06-18T01:52:24Z")

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Hello, I am Dharati

Now I am working on GROMACS for only protein. I tried to generate topology file with amber force field but it is showing this type of error  
Fatal error:  
The residues in the chain LYS1–LEU129 do not have a consistent type. The  
first residue has type ‘Protein’, while residue ALA9 is of type ‘Other’.  
Either there is a mistake in your chain, or it includes nonstandard residue  
names that have not yet been added to the residuetypes.dat file in the GROMACS  
library directory. If there are other molecules such as ligands, they should  
not have the same chain ID as the adjacent protein chain since it’s a separate  
molecule.

So, if you know then can you help me to solve this error???

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