# HADDOCK: Error in DNA PDB File

**URL:** <https://ask.bioexcel.eu/t/haddock-error-in-dna-pdb-file/5569>\
**Category:** HADDOCK\
**Created:** [April 6, 2025, 5:59am UTC](https://ask.bioexcel.eu/t/haddock-error-in-dna-pdb-file/5569 "2025-04-06T05:59:46Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Ska](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Ska](https://ask.bioexcel.eu/u/Ska)\
**Post date:** [April 6, 2025, 5:59am UTC](https://ask.bioexcel.eu/t/haddock-error-in-dna-pdb-file/5569/1 "2025-04-06T05:59:46Z")

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Hi, I’m new to HADDOCK and I have been trying to use it to perform some protein-DNA docking, but I keep getting the following error in my DNA file.

```auto
Error in PDB file.
Issue when parsing the PDB file at line 1.
Your PDB contains an known residue PDBLine: HETATM 1 P DG A 2 119.420 94.732 30.132 1.00 0.00 P that should be using ATOM record, please check the HADDOCK library for a list of supported modified residues.

```

Could anyone suggest what should be done to resolve this issue and/or what is causing it?

Thanks.

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<div class="post-metadata">

**Author:** ![amjjbonvin](https://dub1.discourse-cdn.com/flex013/user_avatar/ask.bioexcel.eu/amjjbonvin/32/23_2.png) [@amjjbonvin](https://ask.bioexcel.eu/u/amjjbonvin)\
**Post date:** [April 6, 2025, 6:35pm UTC](https://ask.bioexcel.eu/t/haddock-error-in-dna-pdb-file/5569/2 "2025-04-06T18:35:34Z")

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define your DNA as ATOM and not HETATM in your PDB file

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<div class="post-metadata">

**Author:** ![Ska](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Ska](https://ask.bioexcel.eu/u/Ska)\
**Post date:** [April 7, 2025, 1:31am UTC](https://ask.bioexcel.eu/t/haddock-error-in-dna-pdb-file/5569/3 "2025-04-07T01:31:33Z")

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Ok, thank you!