# Disassociation of synthetic amino acid after docking

**URL:** <https://ask.bioexcel.eu/t/disassociation-of-synthetic-amino-acid-after-docking/5557>\
**Category:** HADDOCK\
**Tags:** haddock, community\
**Created:** [April 2, 2025, 5:03am UTC](https://ask.bioexcel.eu/t/disassociation-of-synthetic-amino-acid-after-docking/5557 "2025-04-02T05:03:50Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sauda07](https://avatars.discourse-cdn.com/v4/letter/s/e274bd/32.png) [@sauda07](https://ask.bioexcel.eu/u/sauda07)\
**Post date:** [April 2, 2025, 5:03am UTC](https://ask.bioexcel.eu/t/disassociation-of-synthetic-amino-acid-after-docking/5557/1 "2025-04-02T05:03:50Z")

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Hi,  
I ran a protein-peptide docking in Haddock webserver, In result the synthetic amino acid showing disassociation with the peptide . Can I know the reason and how do I solve this problem? Thanks!

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**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 2, 2025, 7:18am UTC](https://ask.bioexcel.eu/t/disassociation-of-synthetic-amino-acid-after-docking/5557/2 "2025-04-02T07:18:04Z")

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The list of supported modified amino acids can be found at:

[

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[HADDOCK Web Server - Settings](https://rascar.science.uu.nl/haddock2.4/library)  
[science.uu.nl](https://rascar.science.uu.nl/haddock2.4/library)

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[![favicon.ico](https://europe1.discourse-cdn.com/flex013/uploads/bioexcel/original/2X/1/107bb531973837ba0aa1bffdc74d58b781de99e8.png)](https://rascar.science.uu.nl/haddock2.4/library)

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](https://rascar.science.uu.nl/haddock2.4/library)

A non-supported modified amino acid defined as HETATM will not get connected to its neighbours and as a result they might “fly out”