# How to generate Hydrogen bond restraints TBL file

**URL:** https://ask.bioexcel.eu/t/how-to-generate-hydrogen-bond-restraints-tbl-file/3173
**Category:** HADDOCK
**Created:** [July 16, 2021, 5:24pm UTC](https://ask.bioexcel.eu/t/how-to-generate-hydrogen-bond-restraints-tbl-file/3173 "2021-07-16T17:24:04Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![vsilva](https://avatars.discourse-cdn.com/v4/letter/v/e9c0ed/32.png) [@vsilva](https://ask.bioexcel.eu/u/vsilva)
#### Post date: [July 16, 2021, 5:24pm UTC](https://ask.bioexcel.eu/t/how-to-generate-hydrogen-bond-restraints-tbl-file/3173/1 "2021-07-16T17:24:04Z")

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Hi all, I’m using the HADDOCK 2.4 webserver to perform a Protein-Ligand Docking.  
I saw I could use hydrogen bond restraints but I don’t know to generate them. I use the [https://alcazar.science.uu.nl/services/GenTBL](https://alcazar.science.uu.nl/services/GenTBL/) to generate the AIR restraints. There’s any tool I can use for that also?

Thanks in advance,  
All the best!

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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: [July 17, 2021, 9:12am UTC](https://ask.bioexcel.eu/t/how-to-generate-hydrogen-bond-restraints-tbl-file/3173/2 "2021-07-17T09:12:07Z")

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The format follows the CNS/Xplor syntax for distance restraints.

See for an example:

> **[Tutorial describing the use of a local version of HADDOCK2.4](https://www.bonvinlab.org/education/HADDOCK24/HADDOCK24-local-tutorial/#defining-specific-distance-restraints)**
>
> A tutorial describing the use a local version HADDOCK2.4

Note that hydrogen bond restraints are only used by default in the refinement stage and will thus not guide the initial docking.  
You can of course define those also simply as unambiguous restraints

You will have to create those restraints files manually (make sure to save them as an ASCII text file).