# Atom H1 in residue ACE 1 was not found in rtp entry

**URL:** <https://gromacs.bioexcel.eu/t/atom-h1-in-residue-ace-1-was-not-found-in-rtp-entry/3771>\
**Category:** User discussions\
**Tags:** pdb2gmx, forcefield, simulation-setup\
**Created:** [March 3, 2022, 11:56am UTC](https://gromacs.bioexcel.eu/t/atom-h1-in-residue-ace-1-was-not-found-in-rtp-entry/3771 "2022-03-03T11:56:27Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Alvaro](https://avatars.discourse-cdn.com/v4/letter/a/839c29/32.png) [@Alvaro](https://gromacs.bioexcel.eu/u/Alvaro)\
**Post date:** [March 3, 2022, 11:56am UTC](https://gromacs.bioexcel.eu/t/atom-h1-in-residue-ace-1-was-not-found-in-rtp-entry/3771/1 "2022-03-03T11:56:27Z")

</div>

GROMACS version:  
GROMACS modification: Yes/No  
Hello, everyone

I’m trying to generate a .gro and .top files from the .pdb structure of polyglycinealanine, using the Amber99 FF. When trying to do so, however, the following error appears:  
Atom H1 in residue ACE 1 was not found in rtp entry ACE with 6 atoms  
while sorting atoms.  
H1 atom is included in the aminoacids.rtp file witht the correct name, and -ignh option doesn’t work either.  
What should I do?

---

<div class="post-metadata">

**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\
**Post date:** [March 3, 2022, 1:39pm UTC](https://gromacs.bioexcel.eu/t/atom-h1-in-residue-ace-1-was-not-found-in-rtp-entry/3771/2 "2022-03-03T13:39:04Z")

</div>

What are you choosing as termini when prompted by `pdb2gmx`? When reporting problems with `pdb2gmx`, please always copy and paste the **entire** screen output and provide it for diagnostic purposes. The complaint about H1 suggests you are using normal N-terminal patching, which is incorrect for a capped polypeptide sequence (for which you need to choose “None” as the terminus type).