# How can I build a unsorported a modified amino acid

**URL:** <https://ask.bioexcel.eu/t/how-can-i-build-a-unsorported-a-modified-amino-acid/923>\
**Category:** HADDOCK\
**Created:** [May 2, 2018, 2:18pm UTC](https://ask.bioexcel.eu/t/how-can-i-build-a-unsorported-a-modified-amino-acid/923 "2018-05-02T14:18:31Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![binbinwang](https://avatars.discourse-cdn.com/v4/letter/b/b5ac83/32.png) [@binbinwang](https://ask.bioexcel.eu/u/binbinwang)\
**Post date:** [May 2, 2018, 2:18pm UTC](https://ask.bioexcel.eu/t/how-can-i-build-a-unsorported-a-modified-amino-acid/923/1 "2018-05-02T14:18:31Z")

</div>

For the question I asked yesterday, I have read haddock protocol paper today. I should define it as cofacto and define distance restraints that mimic a peptide bond between the modified amino acid and the rest of the protein.