# CNS format for small ligand

**URL:** <https://ask.bioexcel.eu/t/cns-format-for-small-ligand/1955>\
**Category:** HADDOCK\
**Created:** [April 26, 2020, 9:39am UTC](https://ask.bioexcel.eu/t/cns-format-for-small-ligand/1955 "2020-04-26T09:39:01Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Leo](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@Leo](https://ask.bioexcel.eu/u/Leo)\
**Post date:** [April 26, 2020, 9:39am UTC](https://ask.bioexcel.eu/t/cns-format-for-small-ligand/1955/1 "2020-04-26T09:39:02Z")

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I read on [https://www.bonvinlab.org/software/haddock2.2/faq/#ligand](https://www.bonvinlab.org/software/haddock2.2/faq/#ligand) that for a small ligand you need to create a CNS file containing parameters and topology. I became a bit confused since I haven´t seen this step described in any other tutorial. Could someone please explain this for me?

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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 26, 2020, 10:03am UTC](https://ask.bioexcel.eu/t/cns-format-for-small-ligand/1955/2 "2020-04-26T10:03:41Z")

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Only if you are using a local version of HADDOCK. The server does it automatically for you 🙂

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**Author:** ![Leo](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@Leo](https://ask.bioexcel.eu/u/Leo)\
**Post date:** [April 26, 2020, 12:23pm UTC](https://ask.bioexcel.eu/t/cns-format-for-small-ligand/1955/3 "2020-04-26T12:23:35Z")

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Okey thank you.for your answer