# Avogadro 2.1.0: Trp aminoacid is with unbound atoms

**URL:** <https://discuss.avogadro.cc/t/avogadro-2-1-0-trp-aminoacid-is-with-unbound-atoms/7563>\
**Category:** Support\
**Created:** [October 23, 2026, 10:46pm UTC](https://discuss.avogadro.cc/t/avogadro-2-1-0-trp-aminoacid-is-with-unbound-atoms/7563 "2026-10-23T22:46:10Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Miroslav\_Ilias](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/miroslav_ilias/32/511_2.png) [@Miroslav\_Ilias](https://discuss.avogadro.cc/u/Miroslav_Ilias)\
**Post date:** [October 23, 2026, 10:46pm UTC](https://discuss.avogadro.cc/t/avogadro-2-1-0-trp-aminoacid-is-with-unbound-atoms/7563/1 "2026-10-23T22:46:10Z")

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Dear support,

with the newest Avogadro 2.1.0 I wantedto build some peptide, but the Trp aminoacid is incomplete, with unbound atoms:

 ![image](https://discuss.avogadro.cc/uploads/default/original/2X/f/f394c59038f2c636c80f15f96b84a5d5e538ce28.png)

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<div class="post-metadata">

**Author:** ![ghutchis](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/ghutchis/32/456_2.png) [@ghutchis](https://discuss.avogadro.cc/u/ghutchis)\
**Post date:** [October 24, 2026, 12:51am UTC](https://discuss.avogadro.cc/t/avogadro-2-1-0-trp-aminoacid-is-with-unbound-atoms/7563/2 "2026-10-24T00:51:53Z")

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That’s weird - sorry. I’ll admit we don’t use Trp in any of our experiments, so I didn’t notice. Probably been there for a while - looks like it’s because Trp uses the generic elements instead of the PDB atom names. (Oh, it looks like a bug in the generating script.)

The big fix is in the `fragments` repository (i.e., the TRP.zmat .. and ARG.zmat too) and there’s a separate minor bug with N+ formal charges building. The continuous release should have it in a few hours.

> <https://github.com/OpenChemistry/avogadrolibs/pull/3230>
>
> Prompted by Miroslav Ilias in the forum (Trp bug)
> \- added entries for SEC, PYL, …AIB, and NME
> \- added a formal charge step for N+ (i.e. bond order four for N)
> 
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