# Docking a protein with a fatty acid side chain

**URL:** <https://ask.bioexcel.eu/t/docking-a-protein-with-a-fatty-acid-side-chain/1571>\
**Category:** HADDOCK\
**Created:** [May 20, 2019, 9:54am UTC](https://ask.bioexcel.eu/t/docking-a-protein-with-a-fatty-acid-side-chain/1571 "2019-05-20T09:54:31Z")\
**Posts on this page:** 1\
**Showing post:** 4

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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:** [May 21, 2019, 2:56pm UTC](https://ask.bioexcel.eu/t/docking-a-protein-with-a-fatty-acid-side-chain/1571/4 "2019-05-21T14:56:51Z")

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Yes you will have to change all "ATOM " to “HETATM” - don’t mess up the columns in doing that.

As for the covalent link to the CYS, I would define an ambiguous distance restraint between your fatty acid and the CYS sulfur atom to keep it in place since HADDOCK won’t generate the covalent bond

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