# First pdb file contains an unknown amino acid or nucleic acid base HID

**URL:** <https://ask.bioexcel.eu/t/first-pdb-file-contains-an-unknown-amino-acid-or-nucleic-acid-base-hid/1532>\
**Category:** HADDOCK\
**Created:** [April 9, 2019, 1:15am UTC](https://ask.bioexcel.eu/t/first-pdb-file-contains-an-unknown-amino-acid-or-nucleic-acid-base-hid/1532 "2019-04-09T01:15:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![1769749405](https://avatars.discourse-cdn.com/v4/letter/1/2bfe46/32.png) [@1769749405](https://ask.bioexcel.eu/u/1769749405)\
**Post date:** [April 9, 2019, 1:15am UTC](https://ask.bioexcel.eu/t/first-pdb-file-contains-an-unknown-amino-acid-or-nucleic-acid-base-hid/1532/1 "2019-04-09T01:15:44Z")

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Dear developers,  
I run a protein-ligand docking.But I found the following error:  
There was an inconsistency in your data

Error message

First pdb file contains an unknown amino acid or nucleic acid base HID

Make sure to use three letter code for bases and amino acid

(upload://8XZyM856cN0u5SXEq7zRvda5Fk4.png) [http://alcazar.science.uu.nl/serviceresults/HADDOCK2.2/6160521422/matrip74](http://alcazar.science.uu.nl/serviceresults/HADDOCK2.2/6160521422/matrip74)  
How do I solve this problem?

Thank you!

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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 9, 2019, 5:34am UTC](https://ask.bioexcel.eu/t/first-pdb-file-contains-an-unknown-amino-acid-or-nucleic-acid-base-hid/1532/2 "2019-04-09T05:34:26Z")

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HID is not a proper amino-acid name according to the PDB… It is used in AMBER and some other software to indicate the protonation state. Simply change it to HIS