# Fatal error: Residue 'EDO' not found in residue topology database

**URL:** <https://gromacs.bioexcel.eu/t/fatal-error-residue-edo-not-found-in-residue-topology-database/5873>\
**Category:** User discussions\
**Created:** [February 25, 2023, 3:21pm UTC](https://gromacs.bioexcel.eu/t/fatal-error-residue-edo-not-found-in-residue-topology-database/5873 "2023-02-25T15:21:30Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\
**Post date:** [March 2, 2023, 2:56pm UTC](https://gromacs.bioexcel.eu/t/fatal-error-residue-edo-not-found-in-residue-topology-database/5873/4 "2023-03-02T14:56:38Z")

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You won’t find an exact solution for your exact residue. But the answer is always the same in every post you will find - `pdb2gmx` can only handle species that already exist in force field `.rtp` files. It’s not magic. If you have a nonstandard species, you have to parametrize it yourself or use external (non-GROMACS) programs to write a topology.

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